JP2007095519A - Organic electroluminescent element and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element which does not have light emission unevenness in pixels or light emission unevenness among the pixels due to flowing-in of ink which has been supplied to barrier ribs existing between patternized first electrodes into partitioned first electrodes when either one of organic light-emitting medium layers is formed by a wet method after a forming material is formed to produce the ink in the organic electroluminescent element equipped with a substrate, the first electrode patternized on this substrate, the organic light-emitting medium layer including an organic light-emitting layer on the first electrode, and a second electrode installed so as to be opposed to the first electrode by pinching the organic light-emitting medium layer. <P>SOLUTION: This is the organic electroluminescent element in which carrier ribs are installed in two rows or more between the first electrodes. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence element (hereinafter referred to as an organic EL element) expected to be used for a display such as an information display terminal, and a method for producing the same.

  An organic EL element is one in which an organic light emitting layer made of an organic light emitting material is formed between two opposing electrodes, and light is emitted by passing a current through the organic light emitting layer. The film thickness is important, and it is necessary to form a thin film of about 100 nm. Furthermore, in order to make this a display, it is necessary to pattern the organic light emitting layer with high definition so that each pixel becomes red (R), green (G), and blue (B).

  Organic light-emitting materials that form the organic light-emitting layer include low-molecular materials and high-molecular materials. Generally, low-molecular materials are formed into a thin film by a dry film-forming method such as resistance heating vapor deposition, and a fine pattern mask is used at this time. However, this method has a problem that the patterning accuracy is less likely as the substrate becomes larger.

Therefore, recently, a method of forming a thin film by a wet film forming method using a polymer material as an organic light emitting material and dispersing or dissolving the organic light emitting material in a solvent to form a coating liquid has been tried. . As a wet film forming method for forming a thin film, there are a spin coating method, a bar coating method, a protruding coating method, a dip coating method, and the like. These wet coating methods are difficult, and it is thought that thin film formation by a printing method that is good at coating and patterning is most effective.

  Further, among various printing methods, in organic EL elements and displays using glass as a substrate, a method using a hard plate such as a metal printing plate such as a gravure printing method is unsuitable, and an elastic rubber blanket. An offset printing method using, and a relief printing method using an elastic rubber plate or resin plate are also suitable. Actually, as an attempt by these printing methods, a method by offset printing (Patent Document 1), a method by letterpress printing (Patent Document 2), and the like have been proposed.

  The organic light-emitting material, which is a material for forming the organic light-emitting layer, has poor solubility in water and alcohol solvents, and it is necessary to dissolve and disperse using an organic solvent in order to form a coating liquid (hereinafter referred to as ink). Among them, organic solvents such as toluene and xylene are preferable. Therefore, the ink of organic light emitting material (hereinafter referred to as organic light emitting ink) is an ink of organic solvent.

  However, the rubber blanket used for offset printing has a problem that it is easily swelled or deformed by toluene or xylene organic solvent. The types of rubber used in blankets vary from olefin rubber to silicone rubber, but none of these rubbers are resistant to toluene, xylene or other solvents and are prone to swelling and deformation. It is not suitable for printing luminescent ink.

In addition, the relief printing method using an elastic relief plate includes a flexographic printing method using a rubber plate and a resin relief plate method using a resinous plate. Among these, a method using a water development type resin relief plate is used. If present, it has high resistance to organic solvents such as toluene and xylene, and can be used for printing organic light-emitting inks.
JP 2001-93668 A JP 2001-155858 A

  In the organic EL element, a partition is formed between the first electrode patterns formed on the substrate. The following two points can be cited as the purpose of forming the partition walls. First, when the first electrode is formed on the entire surface of the device, the photosensitive material is patterned by photolithography, and then the first electrode is etched to form the first electrode pattern. Burr may occur at the edge of the rim. When the edge of the first electrode has burrs, when the organic light emitting medium layer including the organic light emitting layer and the second electrode are formed to form an element, the first electrode and the second electrode are short-circuited and short-circuited. End up. Therefore, the purpose is to cover the edge of the first electrode with a partition wall and prevent a short circuit. Secondly, when an organic light emitting layer is formed by a printing method using an organic light emitting ink in which organic light emitting materials having different emission colors such as red, green and blue are dissolved in a solvent, the concentration of the organic light emitting ink is at most several percent. Since it is usually around 1%, organic light-emitting inks having different emission colors are mixed on the pixels without the partition. Therefore, a partition wall having a certain height is provided between pixels having different emission colors in order to prevent ink color mixture. That is, the purpose is to prevent color mixing.

  For the organic EL element in which the partition is formed between the first electrodes so as to cover the edge between the first electrodes, for example, a hole transport layer which is one of the organic light emitting medium layers is dissolved or dispersed in a solvent. When the hole transport ink is formed on the entire effective surface of the organic EL element by a coating method such as a spin coat method or a die coat method using the ink, the ink is also applied to the partition walls between the patterned first electrodes. Ink is supplied. The partition wall is provided higher than the first electrode because it aims to cover the first electrode and prevent color mixing. Therefore, the ink supplied on the partition between the first electrodes flows into the first electrode partitioned by the partition. By flowing the ink supplied between the first electrodes onto the first electrode, the thickness of the hole transport layer in the vicinity of the partition wall becomes thicker than the thickness of the hole transport layer in the center of the electrode, There has been a problem that uneven light emission occurs in the pixel when the element is formed. In addition, since the amount of ink supplied on the first electrode partitioned by the adjacent partition wall varies depending on the direction in which the ink supplied between the first electrodes flows, the amount of ink supplied for each pixel is reduced. There has been a problem in that variations occur and light emission unevenness occurs between pixels.

  On the other hand, there are a passive matrix method and an active matrix method as a driving method of the organic EL element. The passive matrix method is a method in which stripe-shaped electrodes are opposed to each other so as to be orthogonal to each other, and light is emitted at the intersection, whereas the active matrix method uses a so-called thin film transistor (TFT) substrate in which a transistor is formed for each pixel. Thus, the light is emitted independently for each pixel.

  In the case of an active matrix type organic EL element, the first electrode is formed for each pixel, and the barrier ribs are formed in a grid pattern on the four sides of the first electrode so as to cover the edge of the first electrode. When an organic light-emitting layer is formed by relief printing on a substrate to be printed on which a partition is formed on a lattice so as to cover at least the first electrode as a pixel electrode and the edge of the first electrode on the TFT substrate In view of the problem of dimensional stability of the resin letterpress ink with respect to the solvent, the letterpress plate is not a dot-shaped pattern resin letterpress in which a protrusion is formed for each pixel electrode, but has a stripe pattern in which the line has a protrusion. It is necessary to print.

  That is, when an organic light-emitting layer is formed on an active matrix substrate using a relief printing method, the convex portion of the resin relief plate having a line pattern is continuous with ink so as to straddle the partition between the first electrodes. Supplied and printed. Accordingly, the organic light emitting ink is supplied to both the patterned first electrode and the partition between the first electrodes. Even in such a case, the thickness of the organic light emitting layer in the vicinity of the partition becomes thicker than the thickness of the organic light emitting layer in the center of the electrode due to the flow of ink supplied on the partition between the first electrodes. And there is a variation in the amount of ink supplied for each first electrode surrounded by the partition wall, causing the problem of uneven light emission within the pixels and uneven light emission between the pixels. It was.

  In the present invention, in the case where any one of the organic light emitting medium layers is formed by a wet method using ink as a forming material, the partitioned first electrode of ink supplied to the partition between the patterned first electrodes An object of the present invention is to provide an organic EL element free from uneven light emission within a pixel due to flow into the light source and uneven light emission between pixels.

  The present inventor has devised the arrangement of the partition so that the ink supplied onto the partition does not flow onto the first electrode, so that there is no uneven light emission within the pixel and uneven light emission between the pixels. Could get.

  In order to solve the above problems, an invention according to claim 1 includes a substrate, a first electrode patterned on the substrate, an organic light emitting medium layer including an organic light emitting layer on the first electrode, An organic electroluminescence device comprising a second electrode provided so as to face the first electrode across an organic light emitting medium layer, wherein two or more rows of partition walls are provided between the first electrodes, It was set as the organic electroluminescent element.

  The invention according to claim 2 is that an organic light emitting medium layer forming material is dissolved or dispersed in a solvent to form an ink, and at least one of the organic light emitting medium layers is formed by a wet film forming method using the ink. A method for producing an organic electroluminescent element according to claim 1, wherein the organic electroluminescent element is produced.

  The invention according to claim 3 is characterized in that an organic light emitting material is dissolved or dispersed in a solvent to form an ink, and the organic light emitting layer is formed by a relief printing method using the ink. It was set as the manufacturing method of the luminescence element.

  According to the present invention, by having a plurality of partition walls between the first electrodes, the amount of ink supplied on the partition walls can be reduced, and between the two partition walls formed between the first electrodes. Since the supplied ink can be kept between the first electrodes, the amount of ink flowing from the conventional partition between the first electrodes partitioned by the partition can be reduced, and uneven light emission within the pixel can be achieved. Thus, an organic EL element free from light emission unevenness between pixels could be obtained.

  The organic EL element in the present invention will be described.

  FIG. 1 shows an explanatory cross-sectional view of the organic EL device of the present invention. (B) is an enlarged view of the partition wall portion of (a).

  Hereinafter, the present invention will be described with reference to the drawings. The present invention is applicable to both passive matrix type organic EL elements and active matrix type organic EL elements.

  As shown in FIG. 1, the organic EL element of the present invention has a first electrode 2 on a substrate 1. In the case of the passive matrix system, the first electrode 2 has a stripe pattern. In the case of the active matrix method, the first electrode 2 has a pattern for each pixel.

  The organic EL element of the present invention has an organic light emitting medium layer on the first electrode 2 and in a region (pixel portion) partitioned by the partition walls 7. The organic light emitting medium layer may be composed of an organic light emitting layer alone, or may be composed of a laminated structure of an organic light emitting layer and a light emission auxiliary layer. FIG. 1 shows an organic light emitting medium layer composed of a laminated structure of a hole transport layer 3 which is a light emission auxiliary layer and organic light emitting layers (41, 42, 43). A hole transport layer 3 is provided on the first electrode 2, and a red (R) organic light-emitting layer 41, a green (G) organic light-emitting layer 42, and a blue (B) organic light-emitting layer 43 are provided on the hole transport layer 3. Is provided.

  Furthermore, a second electrode is disposed on the organic light emitting layer. In the case of the passive matrix method, the second electrode is provided in a stripe shape so as to be orthogonal to the first electrode having a stripe shape. In the case of the active matrix method, the second electrode is formed on the entire surface of the organic EL element.

  In the present invention, the partition walls are provided in two or more rows. FIG. 2 shows an explanatory cross-sectional view of a conventional organic EL element. (B) is an enlarged view of the partition wall portion of (a).

  In the present invention, the length L in the width direction of the partition can be made smaller than that of the conventional partition shown in FIG. Accordingly, since the amount of ink supplied onto the partition can be reduced, the amount of ink flowing onto the first electrode partitioned by the partition can be reduced. In addition, in the present invention, the ink supplied between the first electrodes can be kept as extra ink 8 between the partition walls. Therefore, even when ink is supplied between the patterns, the organic EL element is free from uneven light emission within and between pixels.

  In the conventional case as shown in FIG. 2, the ink supplied to the partition walls between the first electrodes flows into one of the first electrodes partitioned by the adjacent partition walls, thereby causing the ink to pass between the pixels. However, in the present invention, the amount of ink supplied between the patterned first electrodes to the first electrodes partitioned by the adjacent partition walls can be reduced.

  FIG. 3 shows an explanatory cross-sectional view of an organic EL element according to another embodiment of the present invention. In this invention, the 1st partition 71 is formed so that the 1st electrode edge may be covered between 1st electrodes, and the 2nd partition 72 is provided in 2 rows on the partition.

  Note that three or more partitions may be provided. When three rows are provided, for example, by increasing the height of the central partition wall, it is possible to effectively prevent color mixing due to intrusion of adjacent organic light-emitting inks having different emission colors.

  Moreover, the example of arrangement | positioning of the partition of this invention was shown in FIG. In the active matrix organic EL element, the first electrode is formed for each pixel. When an organic light emitting layer is formed by a relief printing method using organic light emitting inks having different emission colors from red (R), green (G), and blue (B), the resin plate used in the relief printing method is striped. Ink is also supplied between the first electrodes. The printing direction in the relief printing method is indicated by an arrow Y. At this time, by providing two rows of partition walls between the first electrodes as shown in FIG. 3 with respect to the printing direction Y, the difference in the amount of ink supplied between the pixels having the same luminescent color can be reduced, Unevenness between pixels can be effectively prevented. Further, in FIG. 3, the partition walls between the first electrodes having different emission colors may be two or more rows, and by setting two or more rows, organic light-emitting ink having different emission colors may penetrate into adjacent pixels. Color mixing can be effectively prevented.

  Next, the manufacturing method of the organic EL element according to the present invention will be described.

  As the substrate according to the present invention, any substrate can be used as long as it has an insulating property. In the case of a bottom emission type organic EL element that emits light from the substrate side, it is necessary to use a transparent substrate.

  For example, a glass substrate or a quartz substrate can be used. Further, it may be a plastic film or sheet such as polypropylene, polyethersulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate. Metal oxide thin film, metal fluoride thin film, metal nitride thin film, metal oxynitride thin film, or polymer resin film for the purpose of preventing moisture from entering the organic light emitting medium layer in these plastic films and sheets You may utilize what laminated | stacked these as a board | substrate.

  In addition, it is more preferable to reduce the moisture adsorbed on the inside or the surface of the substrate as much as possible by performing a heat treatment on these substrates in advance. Further, in order to improve the adhesion depending on the material to be laminated on the substrate, it is preferable to use after performing surface treatment such as ultrasonic cleaning treatment, corona discharge treatment, plasma treatment, UV ozone treatment.

  Further, a thin film transistor (TFT) can be formed on these to form a substrate for an active matrix organic EL element. A known thin film transistor can be used as the thin film transistor. Specifically, a thin film transistor mainly including an active layer in which a source / drain region and a channel region are formed, a gate insulating film, and a gate electrode can be given. The structure of the thin film transistor is not particularly limited, and examples thereof include a staggered type, an inverted staggered type, a top gate type, and a coplanar type.

  The active layer is not particularly limited, and examples thereof include inorganic semiconductor materials such as amorphous silicon, polycrystalline silicon, microcrystalline silicon, cadmium selenide, thiophene oligomers, poly (p-ferylene vinylene), and the like. It can be formed of an organic semiconductor material.

These active layers are formed by, for example, depositing amorphous silicon by plasma CVD, ion doping, forming amorphous silicon by LPCVD using SiH ₄ gas, and crystallizing amorphous silicon by solid phase growth. After obtaining silicon, ion doping is performed by ion implantation, LPCVD using Si ₂ H ₆ gas, and amorphous silicon is formed by PECVD using SiH ₄ gas, and laser such as excimer laser is used. After annealing and crystallizing amorphous silicon to obtain polysilicon, polysilicon is deposited by ion doping (low temperature process), low pressure CVD or LPCVD, and thermally oxidized at 1000 ° C. or higher. Gate break Film is formed, a gate electrode of the n + polysilicon is formed thereon, then, a method of ion doping (high temperature process), and the like by an ion implantation method.

  As the gate insulating film, those normally used as the gate insulating film can be used. For example, SiO2 formed by PECVD method, LPCVD method, etc .; SiO2 obtained by thermally oxidizing the polysilicon film, etc. Can be used.

  As a gate electrode, what is normally used as a gate electrode can be used, for example, metals, such as aluminum and copper, refractory metals, such as titanium, tantalum, and tungsten, polysilicon, silicide of a refractory metal, Polycide etc. are mentioned.

  The thin film transistor may have a single gate structure, a double gate structure, or a multi-gate structure having three or more gate electrodes. Moreover, you may have a LDD structure and an offset structure. Further, two or more thin film transistors may be arranged in one pixel. The organic EL element of the present invention needs to be connected so that the thin film transistor functions as a switching element of the organic EL element, and the drain electrode of the transistor and the first electrode of the organic EL element are electrically connected. The thin film transistor, the drain electrode, and the first electrode of the organic EL element are connected via a connection wiring formed in a contact hole that penetrates the planarization film.

  A first electrode is provided on the substrate. When the first electrode is used as an anode, the material is a metal composite such as ITO (indium tin composite oxide), IZO (indium zinc composite oxide), tin oxide, zinc oxide, indium oxide, zinc aluminum composite oxide. A single layer or a stacked layer of metal materials such as oxide, gold, platinum, and chromium can be used. As a method for forming the first electrode, a dry film forming method such as a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, or a sputtering method can be used.

  In addition, ITO is preferably used because of its low resistance, solvent resistance, and high transparency when the bottom mission method is adopted. ITO is formed on a glass substrate by a sputtering method, and is patterned by a photolithography method to form a first electrode.

After forming the first electrode, a partition is formed so as to cover the edge of the first electrode. The partition wall needs to have insulating properties, and a photosensitive material or the like can be used. The photosensitive material may be a positive type or a negative type, and is a photo-curing resin of a photo radical polymerization system, a photo cation polymerization system, or a copolymer containing an acrylonitrile component, polyvinyl phenol, polyvinyl alcohol. , Novolac resin, polyimide resin, cyanoethyl pullulan, and the like can be used. Further, as a partition wall forming _material, it is also possible to use SiO 2, TiO ₂ or the like.

When the partition wall forming material is a photosensitive material, the entire surface of the forming material solution is coated by a slit coating method or a spin coating method, and then patterning is performed by a photolithography method such as exposure and development. In the case of the spin coating method, the height of the partition wall can be controlled by conditions such as the number of rotations when spin coating, but there is a limit height in one coating, and if it is higher than that, multiple spin coatings are performed Use an iterative approach. Further, when the partition wall forming material is SiO ₂ or TiO ₂ , it can be formed by a dry film forming method such as a sputtering method or a CVD method. The patterning of the partition walls can be performed by a mask or a photolithography method.

  Next, an organic light emitting medium layer is formed. The organic light emitting medium layer may be composed of an organic light emitting layer alone, or a light emitting auxiliary layer for assisting light emission, such as an organic light emitting layer and a hole transport layer, a hole injection layer, an electron transport layer, or an electron injection layer. It is good also as a laminated structure. The hole transport layer, hole injection layer, electron transport layer, and electron injection layer are appropriately selected as necessary.

  The organic light emitting layer is a layer that emits light when an electric current is passed. Organic light-emitting materials formed by the organic light-emitting layer include 9,10-diarylanthracene derivatives, pyrene, coronene, perylene, rubrene, 1,1,4,4-tetraphenylbutadiene, tris (8-quinolato) aluminum complex, tris (4-methyl-8-quinolato) aluminum complex, bis (8-quinolato) zinc complex, tris (4-methyl-5-trifluoromethyl-8-quinolato) aluminum complex, tris (4-methyl-5-cyano-) 8-quinolate) aluminum complex, bis (2-methyl-5-trifluoromethyl-8-quinolinolato) [4- (4-cyanophenyl) phenolate] aluminum complex, bis (2-methyl-5-cyano-8-quinolinolato) [4- (4-Cyanophenyl) phenolate] aluminum complex, Lis (8-quinolinolato) scandium complex, bis [8- (paratosyl) aminoquinoline] zinc complex and cadmium complex, 1,2,3,4-tetraphenylcyclopentadiene, poly-2,5-diheptyloxy-paraphenylene vinylene, etc. The low molecular weight light emitting material can be used.

  Further, coumarin phosphors, perylene phosphors, pyran phosphors, anthrone phosphors, polyphyrin phosphors, quinacridone phosphors, N, N′-dialkyl-substituted quinacridone phosphors, naphthalimide phosphors, A material obtained by dispersing a low molecular weight light emitting material such as an N, N′-diaryl-substituted pyrrolopyrrole-based fluorescent pair or a phosphorescent light emitter such as an Ir complex in a polymer can be used. As the polymer, polystyrene, polymethyl methacrylate, polyvinyl carbazole and the like can be used.

  Also, poly (2-decyloxy-1,4-phenylene) (DO-PPP), poly [2,5-bis- [2- (N, N, N-triethylammonium) ethoxy] -1,4-phenyl- Alto-1,4-phenylylene] dibromide (PPP-NEt3 +), poly [2- (2′-ethylhexyloxy) -5-methoxy-1,4-phenylenevinylene] (MEH-PPV), poly [5- Methoxy- (2-propanoxysulfonide) -1,4-phenylenevinylene] (MPS-PPV), poly [2,5-bis- (hexyloxy) -1,4-phenylene- (1-cyanovinylene)] Polymer light-emitting materials such as (CN-PPV) and poly (9,9-dioctylfluorene) (PDAF) may be used. Examples thereof include polymer precursors such as PPV precursor, PNV precursor, and PPP precursor. Further, a material obtained by dispersing or copolymerizing the low-molecular light-emitting material in these polymer materials, or other existing light-emitting materials can also be used.

  As a material for the hole transport layer, metal phthalocyanines such as copper phthalocyanine and tetra (t-butyl) copper phthalocyanine and metal-free phthalocyanines, quinacridone compounds, 1,1-bis (4-di-p-tolylaminophenyl) Cyclohexane, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine, N, N′-di (1-naphthyl) -N, Aromatic amine low molecular hole injection and transport materials such as N′-diphenyl-1,1′-biphenyl-4,4′-diamine, polyaniline, polythiophene, polyvinylcarbazole, poly (3,4-ethylenedioxythiophene) ) And polystyrene sulfonic acid and other polymer hole transport materials, polythiophene oligomer materials, and other existing hole transport materials It is possible to choose from.

  As a material for the electron transport layer, 2- (4-bifinylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (1-naphthyl)- 1,3,4-oxadiazole, an oxadiazole derivative, a bis (10-hydroxybenzo [h] quinolinolato) beryllium complex, a triazole compound, or the like can be used.

  Solvents that dissolve or disperse the organic light emitting material include toluene, xylene, acetone, hexane, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate, 2-methyl- (t-butyl) Benzene, 1,2,3,4-tetramethylbenzene, pentylbenzene, 1,3,5-triethylbenzene, cyclohexylbenzene, 1,3,5-tri-isopropylbenzene and the like can be used alone or in combination. . Moreover, surfactant, antioxidant, a viscosity modifier, a ultraviolet absorber, etc. may be added to organic luminescent ink as needed.

  Solvents that dissolve or disperse the hole transport material and electron transport material include, for example, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate, water, etc. Alternatively, a mixed solvent thereof can be used. In particular, water or alcohols are suitable when forming a hole transport material into an ink.

  The organic light emitting medium layer is formed by a wet film forming method. In the case where the organic light emitting medium layer has a laminated structure, it is not necessary to form all of the layers by a wet film formation method. As the wet film forming method, spin coating method, die coating method, dip coating method, discharge coating method, pre-coating method, roll coating method, bar coating method and the like, relief printing method, inkjet printing method, offset printing method, Examples of the printing method include a gravure printing method. In particular, when an organic light emitting layer is formed, it can be selectively applied to the pixel portion by a printing method. For this reason, it becomes possible to manufacture the organic EL element which can perform a color display by printing to each pixel the light emitting layer which light-emits in a mutually different color.

  In particular, the organic light emitting layer is preferably formed by a relief printing method. Unlike the ink jet method, the relief printing method transfers the ink so that the plate and the printing substrate are in contact with each other, so that the partition wall can be lowered. In the present invention, the letterpress used in the letterpress printing method is preferably a water development type resin letterpress. Examples of the water-developable photosensitive resin constituting the resin plate in the present invention include a type having a hydrophilic polymer and a monomer containing an unsaturated bond, a so-called crosslinkable monomer and a photopolymerization initiator as constituent elements. In this type, polyamide, polyvinyl alcohol, cellulose derivatives and the like are used as hydrophilic polymers. Examples of the crosslinkable monomer include methacrylates having a vinyl bond, and examples of the photopolymerization initiator include aromatic carbonyl compounds. Among these, a polyamide-based water-developable photosensitive resin is preferable from the viewpoint of printability.

  The printing apparatus used for forming the organic light emitting layer can be any relief printing apparatus that prints on a flat plate, but the following printing apparatus is desirable. FIG. 5 shows a schematic diagram of the relief printing apparatus of the present invention. This manufacturing apparatus has a plate cylinder 18 to which an ink tank 10, an ink chamber 12, an anilox roll 14, and a resin relief plate 16 are attached. The ink tank 10 contains organic light-emitting ink diluted with a solvent, and the organic light-emitting ink is fed into the ink chamber 12 from the ink tank 10. The anilox roll 14 rotates in contact with the ink supply section of the ink chamber 12 and the plate cylinder 18.

  As the anilox roll 14 rotates, the organic light emitting ink 14a supplied from the ink chamber 12 is uniformly held on the surface of the anilox roll 14 and then has a uniform film thickness on the convex portions of the resin relief plate 16 attached to the plate cylinder. It will transfer at. Furthermore, the substrate to be printed is fixed on a slidable substrate fixing base, and moved to the printing start position while adjusting the position by the position adjustment mechanism of the plate pattern and the substrate pattern. The convex portion of the resin relief plate 16 further moves while contacting the substrate, and the ink is transferred by patterning to a predetermined position of the substrate 24 to be printed on the stage 20.

  Next, a second electrode is formed. When the second electrode is a cathode, a material having high electron injection efficiency is used as the material. Specifically, a single metal such as Mg, AL, or Yb is used, or a compound such as Li, oxidized Li, or LiF is sandwiched by about 1 nm at the interface in contact with the light emitting medium, and Al or Cu having high stability and conductivity is laminated. And use. Or, in order to achieve both electron injection efficiency and stability, one or more metals such as Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, etc., which have low work function, and stable Ag, Al An alloy system with a metal element such as Cu is used. Specifically, alloys such as MgAg, AlLi, and CuLi can be used. Further, in the case of a top emission type organic EL device, the cathode needs to have transparency, and for example, transparency can be achieved by a combination of these metals and a transparent conductive layer such as ITO.

  As a method for forming the second electrode, a dry film formation method such as a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, or a sputtering method can be used. The thickness is preferably about 10 nm to 1 μm. In the present invention, the first electrode can be a cathode and the second electrode can be an anode.

  And it seals through an adhesive agent with a glass plate, a glass cap, etc., prevents deterioration of the luminescent medium layer etc. by a water | moisture content or oxygen, and becomes an organic EL element.

Using a top emission backplane formed so as to be connected to the first electrode through a contact hole formed in the planarization film so that the thin film transistor functions as a switching element, the pixel number is 240 × 320 dots and the sub pixel It was set to several 720 × 320 dots. Then, chromium (Cr) was patterned by a sputtering method so that the space between the sub-pixels was 40 μm long and 100 μm wide at a pitch of 120 μm × 360 μm to form a first electrode.

  Next, a positive photosensitive material, TELR series (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to the entire effective surface by spin coating. Then, exposure and development processes were performed to form partition walls having an arrangement as shown in FIG. The height of the obtained partition wall is 1.5 μm, and the vertical partition wall width is 50 μm. The width of the horizontal barrier rib was 30 μm, and two horizontal barrier ribs were formed between the first electrodes with a gap of 50 μm. In each partition, the overlapping portion with the first electrode is 5 μm, covers the edge of the first electrode, and surrounds the four sides of the first electrode.

  Next, a 0.1 μm thick poly (3,4-ethylenedioxythiophene) and polystyrene sulfonic acid mixture (hereinafter referred to as PEDOT / PSS) is dispersed in water as a hole transport layer on the first electrode, A film was formed by spin coating. Thereafter, the hole transport ink in unnecessary portions around the effective pixels was removed by wiping with methanol.

  Next, a polyphenylene vinylene derivative, which is an organic light emitting material having red, green, and blue emission colors, was applied to each color by a letterpress printing method using a water-developable photosensitive resin letterpress to form an organic light emitting layer. At this time, using an anilox roll of 150 lines / inch, the film thickness of the obtained organic light emitting layer was 80 nm.

  Next, a 20 nm-thick Ca film was formed by vacuum deposition as the second electrode. After that, an ITO film is formed using a sputtering method, and sealing is performed by sticking a glass plate with a thermosetting adhesive under nitrogen with a dew point of −80 degrees and an oxygen concentration of 1 ppm without exposure to the atmosphere. An EL element was obtained.

  When the lighting display of the panel was confirmed for the obtained organic EL element and the light emission state was checked, no light emission unevenness within the pixel and between the pixels was confirmed.

(Comparative Example 1)
The barrier rib pattern has a height of 1.5 μm, a vertical barrier rib width of 50 μm, a horizontal barrier rib width of 110 μm, an overlapping portion with the first electrode of 5 μm, and a grid-like pattern of one row between the first electrodes. A partition wall was formed. Other steps were the same as in Example 1, and an organic EL device was produced. When the display of the panel was confirmed for the obtained organic EL element and the light emission state was checked, the hole transport layer in the vicinity of the partition wall had a thickness of the hole transport layer in the center of the first electrode in the pixel. The light emission unevenness due to the increase in the film thickness was confirmed. Further, light emission unevenness due to variations in the thickness of the organic light emitting layer was confirmed between pixels having the same light emission color.

Explanatory sectional drawing of the organic EL element of this invention. Explanatory sectional drawing of the conventional organic EL element. Explanatory sectional drawing of the organic EL element of this invention. The example of arrangement | positioning of the partition of this invention. 1 is a schematic view of a relief printing apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 1st electrode 3 Hole transport layer 41 Red organic light emitting layer 42 Green organic light emitting layer 43 Blue organic light emitting layer 7 Partition 71 First partition 72 Second partition 8 Excess ink 10 Ink tank 12 Ink chamber 14 Anilox roll 14a Ink 16 Resin letterpress 18 Plate cylinder 20 Stage 24 Printed substrate

Claims (3)

A substrate, a first electrode patterned on the substrate, an organic light-emitting medium layer including an organic light-emitting layer on the first electrode, and provided so as to face the first electrode across the organic light-emitting medium layer In the organic electroluminescence device comprising the second electrode formed,
An organic electroluminescence device comprising two or more rows of partition walls between the first electrodes.   2. The organic light emitting medium layer forming material is dissolved or dispersed in a solvent to form an ink, and at least one of the organic light emitting medium layers is formed by a wet film forming method using the ink. Manufacturing method of organic electroluminescent element.   2. The method for producing an organic electroluminescent element according to claim 1, wherein an organic light emitting material is dissolved or dispersed in a solvent to form an ink, and the organic light emitting layer is formed by a relief printing method using the ink.

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