JP5672682B2 - Organic EL device and manufacturing method thereof - Google Patents

Description

  The present invention relates to an organic EL element and a manufacturing method thereof, and more particularly to an organic EL element that improves the flatness in a pixel and a manufacturing method thereof.

  An organic EL element has a hole transport layer made of a hole transport material and an organic light emitting layer made of an organic light emitting material formed between two opposing electrodes, and display light emitted from the organic light emitting layer by passing an electric current. Is extracted from the light transmissive electrode. As described above, the organic EL element is being developed as a light-emitting element capable of high-luminance light emission by direct current low-voltage driving despite its simple structure.

  The type of organic EL element depends on the organic light emitting material used for the organic light emitting layer. The organic EL element using a low molecular organic light emitting material (hereinafter referred to as “low molecular organic EL element”) and the organic using a high molecular organic light emitting material It is roughly classified into EL elements (hereinafter referred to as “polymer organic EL elements”).

  A low molecular organic EL element generally forms a thin film by a dry coating method such as a vacuum deposition method. When patterning of a hole transport layer or an organic light emitting layer is required as an organic EL display device, patterning is performed using a metal mask or the like, but this method has a problem that patterning accuracy is less likely to occur as the substrate becomes larger. There is. In addition, since the film is formed in a vacuum, there is a problem that the throughput is poor. In addition, it is easily affected by the unevenness of the base, which may cause display unevenness.

  High molecular organic EL devices have been tried to form a thin film by a wet coating method by dissolving an organic light emitting material in a solvent to form a coating solution. The wet coating method for forming a thin film includes a spin coating method, a bar coating method, a protruding coating method, a dip coating method, etc., but patterning with high definition or R (red), G (green) and B (blue) ), It is difficult to use these wet coating methods, and it is considered that thin film formation by a printing method that is good at coating and patterning is most effective.

  Among various printing methods, a glass substrate is often used as a substrate in organic EL elements and organic EL display devices, so a method using a hard plate such as a metal printing plate such as a gravure printing method is not suitable. In addition, an offset printing method using an elastic rubber blanket and a relief printing method using an elastic rubber plate or a photosensitive resin plate are also appropriate. In fact, as an attempt by these printing methods, for example, Patent Document 1 discloses a method using offset printing (see Patent Document 1), and Patent Document 2 discloses a method using letterpress printing (Patent Document 1). 2).

  Similar to organic light-emitting materials, low-molecular organic materials and high-molecular organic materials are usually used as hole transport materials. As a typical example of a low molecular hole transport material, Patent Document 3 discloses, for example, a technique using TPD (triphenyleneamine derivative) (see Patent Document 3). In Document 4, for example, a technique using PEDOT: PSS (a mixture of polythiophene and polystyrene sulfonic acid) is disclosed (see Patent Document 4). The film forming method of the hole transport material is a dry coating method or a wet coating method as in the organic light emitting material.

  In addition to the organic light emitting layer and the hole transport layer, a carrier injection layer (also referred to as a carrier transport layer) is formed between the electrodes. The carrier injection layer controls the amount of injected electrons when injecting electrons from the electrode into the organic light emitting layer, or the amount of injected holes when holes are injected from the other electrode into the organic light emitting layer. This is a layer used for controlling the thickness and is a layer inserted between the electrode and the organic light emitting layer. As the electron injection layer, an electron transporting organic substance such as a metal complex of a quinolinol derivative or a relatively small work function such as Ca or Ba such as an alkali metal is used, or a plurality of layers having these functions are stacked. In some cases. As a hole injection layer of an organic material, for example, Patent Document 5 discloses a technique using TPD (triphenyleneamine derivative) (see Patent Document 5), and Patent Document 6 discloses, for example, PEDOT: PSS (polythiophene and polystyrene). A technique using a mixture of sulfonic acids) is disclosed. Alternatively, Patent Document 7 discloses, for example, a technique using an inorganic hole transport material (see Patent Document 7).

  In addition, by stacking an interlayer between the organic light emitting layer and the carrier injection layer, the organic light emitting layer is prevented from being dissolved, the electron blocking action, the mass transfer from the carrier injection layer and the energy transfer from the organic light emitting layer are prevented. From these effects, it can be expected that the organic EL element will have a long lifetime and high efficiency. Examples of the interlayer include a polymer containing an aromatic amine having an aromatic amine in the side chain or main chain. Here, a layer including an organic light emitting layer, a hole transport layer, a carrier injection layer, and an interlayer formed between the electrodes is referred to as a light emitting medium layer.

  Ideally, it is possible to bring out performance by using different light emitting medium layers for each of RGB, but since the number of steps in the mass production process increases and high-definition patterning is difficult, the light emitting medium layer In general, a coating film common to RGB is formed.

  However, various luminescent medium layers have the property of being cured by firing at a certain temperature or higher. Therefore, if the film thickness is too thick, the baking temperature is too low, or the baking time is too short, the curing will not proceed sufficiently, causing a reduction in the film when various luminescent medium layers are applied and the cause of the dissolution reaction at the interface End up.

  Furthermore, when applying to a pixel using the wet coating method, the film thickness in the vicinity of the partition wall that separates the pixel by the wet liquid becomes extremely thick, and a phenomenon occurs in which the central portion of the pixel shines strongly. In this case, since the region that shines strongly becomes narrow, in order to obtain the overall luminance of the organic EL display device, a larger amount of current flows, and the load on the center portion of the pixel increases, resulting in a luminance life and luminous efficiency. It will be greatly reduced.

JP 2001-93668 A JP 2001155858 A Japanese Patent No. 2916098 Japanese Patent No. 2851185 Japanese Patent No. 2916098 Japanese Patent No. 2851185 JP-A-9-63771

  An object of the present invention is to provide an organic EL element that can emit light uniformly in a pixel and a manufacturing method thereof by improving the flatness in the pixel and reducing a load on a local light emitting material.

According to a first aspect of the present invention, a substrate is prepared, a partition wall is formed between the plurality of first electrodes on the substrate, and protrudes so as to cover an end portion of the first electrode. the interlayer of the plurality of light emitting medium layer comprising the organic light-emitting layer was formed by a wet coating method in the vicinity of the upper and protruding septum, curing the interlayer on the first electrode, in the vicinity of the partition wall projecting as part of the interlayer is uncured, the heat from the surface opposite to the interlayer and the formed surface, to remove the uncured portions of the interlayer, the second on the inter-layer electrode is formed, said partition wall which protrudes form the following height 2μm or 0.5 [mu] m, the inter layer and forming by the wet coating method so as to cover the partition wall for the protruding organic This is a method for manufacturing an EL element.

The invention according to claim 2 of the present invention is the method for producing an organic EL element according to claim 1, wherein the temperature at which the interlayer is baked is 150 ° C. or higher and 250 ° C. or lower. is there.

Invention, a method of manufacturing an organic EL element according to claim 1 or claim 2, wherein the time for calcination treatment the interlayer is less than 30 minutes than 10 minutes according to claim 3 of the present invention It is what.

Billing invention according to claim 4 of the present invention, characterized in that the removal by washing away the thick places inter-layer formed in the vicinity of the partition wall projecting inorganic solvent, an organic solvent or a mixture of these solutions It is set as the manufacturing method of the organic EL element in any one of Claims 1 thru | or 3 .

Invention, and characterized by removing by exposing the thick film locations of the inter-layer formed in the vicinity of the partition wall projecting inorganic solvent, the vapor of an organic solvent or a mixture of these solutions according to Claim 5 of the present invention The method for producing an organic EL element according to any one of claims 1 to 3 is provided.

The invention according to claim 6 of the present invention is an organic EL element formed by using the method for producing an organic EL element according to any one of claims 1 to 5 .

An invention according to claim 7 of the present invention is an image display device comprising an organic EL element formed by using the method for manufacturing an organic EL element according to any one of claims 1 to 5. It is a thing.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the organic EL element which can make the inside of a pixel light-emit uniformly by improving the flatness in a pixel and reducing the load to a local luminescent material can be provided. .

It is a schematic sectional drawing which shows the organic EL element which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the organic EL element of 3 pixels of red, green, and blue which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the thick film location of the interlayer formed in the partition wall vicinity of the conventional organic EL element.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment, the same components are denoted by the same reference numerals.

  The organic EL element 100 according to the embodiment of the present invention can be applied to a method for manufacturing the organic EL element 100 including a step of forming a luminescent medium layer by coating and baking. Hereinafter, although it demonstrates about the case where it applies to the interlayer formed between the 1st electrode 2 and the organic light emitting layer 5, this invention is not necessarily limited to this.

  FIG. 1 is a schematic cross-sectional view showing an organic EL element 100 according to an embodiment of the present invention. As shown in FIG. 1, an organic EL element 100 according to an embodiment of the present invention is formed to face a substrate 1, a first electrode 2 formed on the substrate 1, and the first electrode 2. A second electrode 7 and a light emitting medium layer 6 sandwiched between the first electrode 2 and the second electrode 7 are provided. The light emitting medium layer 6 includes at least an organic light emitting layer 5 that contributes to light emission, and a first carrier injection layer 3 and an interlayer 4 as a carrier injection layer for injecting electrons or holes. The interlayer 4 includes an electron injection layer and a hole blocking layer (not shown) between the second electrode 7 and the organic light emitting layer 5, and a hole between the first electrode 2 and the organic light emitting layer 5. An injection layer, an electron block layer, and the like can be laminated as necessary. Moreover, since the light emitting medium layer 6 described above is easily deteriorated by moisture and oxygen in the atmosphere, a sealing body 9 that is shielded from the outside and a sealing resin 10 that adheres the sealing body 9 are used. The organic EL element is sealed.

  Next, in the organic EL element 200 shown in FIG. 2, the partition wall 8 that partitions the light emitting medium layer 6 with the first electrode 2 on the substrate 1 being separated will be described. An organic EL element 200 shown in FIG. 2 has a partition 8 that forms a first electrode 2 on a substrate 1 and partitions a light emitting medium layer 6 at an end of the first electrode 2. By arranging such organic EL elements 200 as pixels (subpixels), an organic EL display device can be obtained. For example, as shown in FIG. 2, a full-color organic EL display device can be produced by coating the organic light-emitting layer 5 with three colors of a red organic light-emitting layer 5R, a green organic light-emitting layer 5G, and a blue organic light-emitting layer 5B. it can.

In the organic EL element 20 according to the embodiment of the present invention shown in FIG. 2, the first carrier injection layer 3 is formed between the first electrode 2 and the organic light emitting layer 5, and the first carrier injection layer 3 is formed. Is at least partially sandwiched between the partition walls 8. That is, the first carrier injection layer 3 is formed on the substrate 1 and between the adjacent partition walls 8. Furthermore, the interlayer 4 is formed so as to cover the entire surface of the first electrode 2 on the substrate 1, and the second electrode 7 includes a partition wall 8 and an organic light emitting layer 5 on the substrate 1, and is striped according to the driving method. It is formed so as to cover the entire surface.
ing.

  However, when the interlayer 4 is formed so as to cover the entire surface of the first electrode 2, a thick film portion is formed on the partition wall 8 as shown in FIG. 3. As a result, the film thickness in the vicinity of the partition wall 8 becomes extremely thick, and a phenomenon occurs in which the central portion of the pixel shines strongly. That is, the film thickness of the interlayer 4 is removed by removing a portion having a film thickness in the vicinity of the partition wall 8 which causes a phenomenon in which the central portion of the pixel shines strongly, and removing it using an inorganic solvent, an organic solvent or a mixed solution thereof. By flattening, light emission can be kept uniform.

  Even in the case of the light emitting medium layer 6 other than the interlayer 4, it can be applied as long as it is cured by heat and an uncured portion can be removed with a solvent or the like. In the baking step for thermosetting, the region of the light emitting medium layer 6 formed on the first electrode 2 needs to be cured. And the thick film formation part of the partition 8 surface is made into an unexposed state. Therefore, as a heating method, it is preferable to heat from the substrate 1 side with a hot plate or the like so as to have a thermal gradient in the film surface direction of the light emitting medium layer 6. If it does in this way, the thick film part of the luminescent medium layer 6 can be adjusted to the uncured state from the 2nd electrode 7 side by control of temperature or a heating time. The temperature at which the luminescent medium layer 6 is fired at this time is preferably 150 ° C. or higher and 250 ° C. or lower. Moreover, it is preferable that the time which bakes the luminescent medium layer 6 is 10 minutes or more and 30 minutes or less. Here, if the temperature when firing the luminescent medium layer 6 exceeds 250 ° C., the film thickness of the luminescent medium layer 6 is reduced. If the temperature is lower than 150 ° C., dissolution at the interface of the stacked luminescent medium layers 6 occurs. A reaction will occur. When the time for firing the light emitting medium layer 6 exceeds 30 minutes, the light emitting medium layer 6 including the thick film forming portion is exposed, and when the time for firing the light emitting medium layer 6 is less than 10 minutes, The thick film forming portion cannot be brought into an unexposed state.

  Next, an inorganic solvent, an organic solvent or a mixed solution thereof is applied onto the substrate 1 to wash away uncured portions and remove them. As the solvent at this time, for example, an ink solvent at the time of applying the light emitting medium layer 6 to be removed can be used. Thereafter, the solvent is removed by a drying process such as heating, whereby the uncured portion is removed and the thick film portion near the partition wall 8 can be flattened. At this time, it is ideal to adjust and remove the uncured portion so as to be equal to the film thickness at the center of the display area on the first electrode 2.

  Hereinafter, the configuration of the organic EL element according to the embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. As an example for explaining the organic EL element of the embodiment of the present invention, an organic EL element using the first electrode 2 as an anode and the second electrode 7 as a cathode will be described. In this case, the first electrode 2 is formed as a pixel electrode partitioned by the partition wall 8 for each pixel, and the second electrode 7 is a counter electrode formed on the entire surface of the substrate 1. The first carrier injection layer 3 and the interlayer 4 are hole transporting hole injection layers. The present invention is not limited to this, and for example, an organic EL element in which each electrode is formed in a stripe shape orthogonal to each other may be used. Moreover, it is good also as an organic EL element of the reverse structure which used the 1st electrode 2 side as the cathode. In this case, the first carrier injection layer 3 and the interlayer 4 are electron transporting electron injection layers.

<Substrate 1>
As the substrate 1 of the organic EL element, any material can be used as long as it is a substrate having mechanical strength and insulation and excellent dimensional stability. As the substrate 1, for example, glass, quartz, polypropylene, polyether sulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, or the like, or these plastic films And metal oxides such as silicon oxide and aluminum oxide, metal fluorides such as aluminum fluoride and magnesium fluoride, metal nitrides such as silicon nitride and aluminum nitride, metal oxynitrides such as silicon oxynitride, acrylic Translucent substrate made of single layer or laminated polymer resin film such as resin, epoxy resin, silicon resin, polyester resin, metal foil such as aluminum or stainless steel, sheet, plate, plastic film or sheet Aluminum, may be used copper, nickel, stainless steel and metal film non-translucent substrate as a laminate of such. The substrate 1 may be a substrate in which a thin film transistor is formed in advance. In the organic EL element 100, the translucency of the substrate 1 may be selected depending on which surface the light extraction is performed from. The substrate 1 made of the above-described material is subjected to moisture-proofing treatment or hydrophobic treatment by forming an inorganic film or applying a fluororesin in order to prevent moisture from entering the display device of the organic EL element. It is preferable. In particular, in order to avoid intrusion of moisture into the light emitting medium layer 6, it is preferable to reduce the moisture content and gas permeability coefficient in the substrate 1.

<Pixel electrode>
The first electrode 2 is formed on the substrate 1 and patterned as necessary. In the embodiment of the present invention, the first electrode 2 is partitioned by the partition wall 8 and becomes a pixel electrode corresponding to each pixel. Examples of the material of the first electrode 2 include metal composite oxides such as ITO (indium tin composite oxide), indium zinc composite oxide and zinc aluminum composite oxide, metal materials such as gold and platinum, and these metals. Either a single layer or a laminate of fine particle dispersion films in which fine particles of an oxide or a metal material are dispersed in an epoxy resin or an acrylic resin can be used. When the pixel electrode is the first electrode 2, it is preferable to select a material having a high work function such as ITO. In the case of a so-called bottom emission structure in which light is extracted from below (substrate 1 side), it is necessary to select a light-transmitting material. If necessary, a metal material such as copper or aluminum may be provided as an auxiliary electrode in order to reduce the wiring resistance of the pixel electrode. Depending on the material, the pixel electrode is formed by a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, a sputtering method, or a dry film forming method, a gravure printing method, or a screen printing method. A wet film forming method such as can be used. As a patterning method of the pixel electrode, an existing patterning method such as a mask vapor deposition method, a photolithography method, a wet etching method, or a dry etching method can be used depending on a material and a film forming method.

<Partition wall 8>
A photosensitive insulating resin is applied on the substrate 1 on which the first electrode 2 is formed. Next, the pattern of the partition walls 8 is formed by pattern exposure and development of the photosensitive insulating resin. And after baking the pattern of the partition 8, it light-irradiates etc. and is made hydrophilic, The partition 8 is formed.

  As a method for forming the partition wall 8, as in the prior art, an inorganic film is uniformly formed on the substrate 1 on which the first electrode 2 is formed, masked with a resist, and then dry etching is performed, or the first electrode 2 is formed. There is a method in which a photosensitive resin is laminated on the substrate 1 on which is formed and a predetermined pattern is formed by photolithography. If necessary, a water repellent can be added, or liquid repellency can be imparted to the ink after being formed by irradiation with plasma or UV. A preferable height of the partition wall 8 is not less than 0.1 μm and not more than 10 μm, and more preferably not less than 0.5 μm and not more than 2 μm. If the height of the partition wall 8 is higher than 10 μm, the formation and sealing of the counter electrode 7 is hindered. If the height of the partition wall 8 is too lower than 0.1 μm, the end of the pixel electrode cannot be covered, or When the light emitting medium layer 6 is formed, it mixes with adjacent pixels.

  The photosensitive resin for forming the partition wall 8 may be either a positive resist or a negative resist, and an insulating photosensitive resin can be used. When a voltage is applied to a certain pixel when the partition wall 8 does not have sufficient insulation, a current also flows to a pixel adjacent to the pixel with the partition wall 8 interposed therebetween, resulting in a display defect. Specific examples of the photosensitive resin forming the partition wall 8 include resins such as polyimide, acrylic resin, novolak resin, and fluorene, but are not limited thereto. Further, for the purpose of improving the display quality of the organic EL element, a light shielding material may be contained in the photosensitive resin.

  The photosensitive resin for forming the partition wall 8 is applied using a coating method such as a spin coating method, a bar coating method, a roll coating method, a die coating method, or a gravure coating method. In the step of pattern exposure and development of the applied photosensitive resin to form the pattern of the partition wall 8, the pattern of the portion that becomes the partition wall 8 can be formed by the exposure and development method. Moreover, regarding the baking process of the partition 8, it can bak by the method with an oven, a hotplate, etc.

  In the step of making the fired pattern of the barrier ribs 8 hydrophilic by irradiating light, ultraviolet rays or the like are irradiated from the upper surface of the substrate 1 on which the barrier rib 8 pattern is formed (the surface on which the first electrode 2 on the substrate 1 is formed). Thus, the portion that becomes the partition wall 8 and the portion of the first electrode 2 are hydrophilized. As the light to be irradiated, ultraviolet rays generally used for ultraviolet cleaning such as hydrophilization treatment are preferable, and ultraviolet irradiation treatment using an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, or the like is preferable. The hydrophilic treatment step is preferably performed immediately before the carrier injection layer 3 is formed.

<Carrier injection layer 3>
The carrier injection layer 3 is formed in a pattern or on the entire surface so as to cover the first electrode 2. Examples of the hole transport material forming the carrier injection layer 3 include polyaniline derivatives, polythiophene derivatives, polyvinylcarbazole (PVK) derivatives, poly (3,4-ethylenedioxythiophene) (PEDOT), and the like. These materials are dissolved or dispersed in a solvent, and are formed by various coating methods using a spin coating method or the like and a relief printing method.

In addition, when an inorganic material is used as the hole transport material, examples of the inorganic material include Cu ₂ O, Cr ₂ O ₃ , Mn ₂ O ₃ , FeOx (x to 0.1), NiO, CoO, Pr ₂ O ₃ , Ag. Transition metal oxides such as ₂ O, MoO ₂ , Bi ₂ O ₃ , ZnO, TiO ₂ , SnO ₂ , ThO ₂ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , MoO ₃ , WO ₃ , MnO ₂ And inorganic compounds containing one or more of these nitrides and sulfides can be used. However, the material is not limited to these. Inorganic materials are preferable because many materials are excellent in heat resistance and electrochemical stability. These can be formed as a single layer or a stacked structure of a plurality of layers, or a mixed layer. The preferred film thickness of the hole transport layer (carrier injection layer) 3 is 5 nm or more, more preferably about 15 nm or more. As a method for forming the hole transport layer 3, depending on the material, 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, a sputtering method, a spin coating method, Existing film forming methods such as a wet coating method such as a sol-gel method can be used, but the present invention is not limited to these, and a general film forming method can be used.

<Interlayer 4>
After forming the carrier injection layer 3, the interlayer 4 is formed so as to cover the partition wall 8. Examples of the material used for the interlayer 4 include polymers containing aromatic amines such as polyvinyl carbazole or derivatives thereof, polyarylene derivatives having aromatic amines in the side chain or main chain, arylamine derivatives, and triphenyldiamine derivatives. . These materials are dissolved or dispersed in water, an organic solvent or a mixed solvent thereof, and formed as an ink by a wet coating method.

  As the organic solvent, toluene, xylene, anisole, mesitylene, tetralin, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate and the like can be used. Further, a surfactant, an antioxidant, a viscosity modifier, an ultraviolet absorber and the like may be added to the ink. As a method for forming the interlayer 4, an existing film forming method such as a spin coating method, a sol-gel method, or a wet coating method can be used. Can be used.

  The interlayer 4 is crosslinked and cured by firing. Therefore, as described above, by heating from the first electrode 2 side (substrate 1 side) during the baking treatment, a part of the thick film region that has run over the partition wall 8 is made uncured, and the uncured part is made with a solvent. By washing away, the interlayer 4 with high flatness can be formed.

<Organic light emitting layer 5>
After forming the interlayer 4, the organic light emitting layer 5 is formed. The organic light emitting layer 5 is a layer that emits light by passing an electric current. When the display light emitted from the organic light emitting layer 5 is monochromatic, the organic light emitting layer 5 is formed so as to cover the interlayer 4, but obtains multicolor display light. Can be suitably used by performing patterning as necessary.

  Examples of the organic light-emitting material forming the organic light-emitting layer 5 include coumarin-based, perylene-based, pyran-based, anthrone-based, porphyrin-based, quinacridone-based, N, N′-dialkyl-substituted quinacridone-based, naphthalimide-based, N, N′-. Diaryl-substituted pyrrolopyrrole, iridium complex, and other luminescent dyes dispersed in polymers such as polystyrene, polymethylmethacrylate, and polyvinylcarbazole, and polyarylene, polyarylene vinylene, and polyfluorene polymers Examples of the material include, but are not limited to, the present invention.

  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 them, aromatic organic solvents such as toluene, xylene, and anisole are preferable from the viewpoint of the solubility of the organic light emitting material. Moreover, you may add surfactant, antioxidant, a viscosity modifier, a ultraviolet absorber etc. to organic luminescent ink as needed.

  In addition to the polymer materials described above, 9,10-diarylanthracene derivatives, pyrene, coronene, perylene, rubrene, 1,1,4,4-tetraphenylbutadiene, tris (8-quinolato) aluminum complex, tris (4-methyl) -8-quinolate) aluminum complex, bis (8-quinolate) zinc complex, tris (4-methyl-5-trifluoromethyl-8-quinolate) 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, tris (8-quino) Norato) scandium complex, bis [8- (para-tosyl) aminoquinoline] zinc complex and cadmium complex, 1,2,3,4-tetraphenylcyclopentadiene, poly-2,5-diheptyloxy-para-phenylene vinylene A low molecular weight light emitting material such as can be used.

  As a method for forming the organic light emitting layer 5, depending on the material, dry film forming methods such as resistance heating vapor deposition, electron beam vapor deposition, reactive vapor deposition, ion plating, and sputtering, ink jet printing, letterpress Existing film forming methods such as a wet film forming method such as a printing method, a gravure printing method, and a screen printing method can be used, but the present invention is not limited thereto.

<Electron injection layer>
After the organic light emitting layer 5 is formed, a hole blocking layer, an electron injection layer, and the like are formed. These functional layers (light emitting medium layer 6) can be arbitrarily selected from the size of the organic EL display device and the like. The material used for the hole blocking layer and the electron injection layer may be any material that is generally used as an electron transport material, such as triazole, oxazole, oxadiazole, silole, and boron. A film can be formed by a vacuum deposition method using a material, an alkali metal such as lithium fluoride or lithium oxide, or a salt or oxide of an alkaline earth metal. In addition, these electron transport materials and these electron transport materials are dissolved in polymers such as polystyrene, polymethyl methacrylate, polyvinyl carbazole, etc., and toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol , Ethyl acetate, butyl acetate, water or the like alone or in a mixed solvent to form an electron injection coating solution, which can be formed by a printing method.

<Second electrode 7>
Next, the second electrode 7 is formed. When the second electrode 7 is a cathode, a substance having a high electron injection efficiency into the organic light emitting layer 5 and a low work function is used. 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 layer 6, and Al or Cu having high stability and conductivity. May be used in a stacked manner. Alternatively, 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, and Yb having a low work function and stable Ag, Al An alloy system with a metal element such as Cu or Cu may be used. Specifically, alloys such as MgAg, AlLi, and CuLi can be used.

  As a method for forming the second electrode 7, 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 depending on the material.

<Sealing body 9>
The organic EL element 100 can emit light by sandwiching an organic light emitting material between electrodes and passing an electric current. However, since the organic light emitting material is easily deteriorated by moisture and oxygen in the atmosphere, it is usually external. A sealing body 9 is provided for blocking. The sealing body 9 can be manufactured, for example, by providing a sealing resin 10 on a sealing material.

The sealing material needs to be a base material having low moisture and oxygen permeability. Examples of the material include ceramics such as alumina, silicon nitride, and boron nitride, glass such as alkali-free glass and alkali glass, quartz, and moisture resistant film. Examples of moisture-resistant films include films formed by CVD of SiOx on both sides of plastic substrates, films with low permeability and water-absorbing films, or polymer films coated with a water-absorbing agent. The water vapor transmission rate is preferably 10 ⁻⁶ g / m ² / day or less.

  As an example of the material of the sealing resin 10, a photocurable adhesive resin, a thermosetting adhesive resin, a two-component curable adhesive resin made of epoxy resin, acrylic resin, silicon resin, or the like, or ethylene ethyl acrylate ( EEA) Acrylic resins such as polymers, vinyl resins such as ethylene vinyl acetate (EVA), thermoplastic resins such as polyamide and synthetic rubber, and thermoplastic adhesive resins such as acid-modified products of polyethylene and polypropylene. it can. Examples of methods for forming a resin layer on a sealing material include solvent solution method, extrusion lamination method, melting / hot melt method, calendar method, nozzle coating method, screen printing method, vacuum laminating method, hot roll laminating method, etc. Can be mentioned. A material having a hygroscopic property or an oxygen absorbing property may be contained as necessary. Although the thickness of the resin layer formed on a sealing material is arbitrarily determined by the magnitude | size and shape of the organic EL element to seal, 5 micrometers-500 micrometers are desirable. In addition, although it formed as sealing resin 10 on the sealing material here, it can also form directly in the organic EL element side.

  Finally, the organic EL element and the sealing body 9 are bonded together in a sealing chamber. When the sealing body 9 has a two-layer structure of a sealing material and a sealing resin 10 and a thermoplastic resin is used for the sealing resin 10, it is preferable to perform only pressure bonding with a heated roll. When a thermosetting adhesive resin is used, it is preferable to perform heat curing at a curing temperature after pressure bonding with a heated roll. In the case where a photocurable adhesive resin is used, curing can be performed by further irradiating light after pressure bonding with a roll.

  In the organic EL device according to the embodiment of the present invention, the firing time and firing conditions of the light emitting medium layer 6 are adjusted at a thick portion near the partition wall 8 formed when the light emitting medium layer 6 is applied by the wet coating method. Then, by removing the uncured thick film portion formed in the vicinity of the partition wall 8, the flatness within the pixel is improved, and the load on the local light emitting material is reduced, so that the organic EL element emits light uniformly. be able to.

  Examples of the organic EL device of the present invention will be described below, but the present invention is not limited to the examples.

  First, a 1.8 inch diagonal glass substrate was prepared as the substrate 1. Next, an ITO (indium-tin oxide) thin film is formed on the glass substrate 1 by sputtering, a pattern of the first electrode 2 is drawn by photolithography, and the ITO film is patterned by etching with an acid solution. First electrode 2 was formed. The line pattern of the first electrode 2 was a pattern in which a line width of 136 μm, a space of 30 μm, and a line of 192 lines formed in about 32 mm square.

  Next, the partition wall 8 was formed. For the partition wall 8, a positive photosensitive polyimide displayed by Toray Co., Ltd., Photo Nice, trade name “DL-1000” was spin coated on the glass substrate 1 on which the first electrode 2 was formed. The spin coating was performed at 150 rpm for 5 seconds and then at 500 rpm for 20 seconds to form a single coating. The photosensitive polyimide was applied with a thickness of about 1.5 μm so that the height of the partition wall 8 was 1.5 μm. Next, the photosensitive polyimide applied on the entire surface was exposed and developed by a photolithography method to form a line pattern of a portion to be the partition wall 8 disposed between the first electrodes 2. The pattern of the partition walls 8 was baked in an oven at 230 ° C. for 30 minutes to form the partition walls 8.

Next, the substrate before printing the first carrier injection layer (hole transport layer) 3 (the substrate 1 on which the first electrode 2 and the partition wall 8 are formed) is manufactured by Oak Seisakusho, UV / O ₃ cleaning. The device was made hydrophilic by irradiating with ultraviolet rays for 3 minutes. As an ink for forming the hole transport layer 3 on a hydrophilized substrate, a 1 wt% aqueous dispersion of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid (hereinafter PEDOT / PSS) is used as a printing method. The film was formed so that the portion serving as a display region had a film thickness of 70 nm, and baked in the air at 200 ° C. for 15 minutes.

  Next, the substrate (the first electrode 2, the hole transport layer 3, and the partition wall 8 is formed using an ink in which a polyvinyl carbazole derivative, which is the material of the interlayer 4, is dissolved in toluene so as to have a concentration of 0.5%. The substrate 1) was formed by spin coating so that the portion serving as the display region had a thickness of 30 nm, and the luminescent medium layer was baked in the atmosphere at 200 ° C. for 15 minutes.

  Thereafter, a thick film portion of the interlayer 4 formed in the vicinity of the partition wall 8 that could not be cured by baking at 200 ° C. for 15 minutes was washed away with toluene. When the patterning state of the luminescent medium layer 6 after cleaning was observed, the luminescent medium layer 6 in each pixel maintained a uniform film shape, and in the vicinity of the partition wall 8 of the interlayer 4 formed in the vicinity of the partition wall 8. It was confirmed that the thick film formed was removed cleanly. At this time, the thickness of the light emitting medium layer 6 was 20 nm.

  An organic light emitting ink in which a polyphenylene vinylene derivative, which is an organic light emitting material, is dissolved in toluene so as to have a concentration of 1% is used, and the line pattern is formed immediately above the first electrode 2 in the pixel portion sandwiched between the partition walls 8. In addition, the organic light emitting material was printed by a relief printing method to form the organic light emitting layer 5 and dried. The thickness of the organic light emitting layer 5 after printing and drying was 100 nm.

  Next, a second electrode 7 made of Ca and Al was formed on the organic light emitting layer 5 by mask vapor deposition using a resistance heating vapor deposition method in a line pattern orthogonal to the line pattern of the first electrode 2. The organic EL element 20 is formed by the above procedure, and finally, the organic EL element is covered with a glass cap as the sealing body 9 in order to protect it from external oxygen and moisture, and an adhesive as the sealing resin 10 is used. Then, a glass cap was adhered to hermetically seal the organic EL element 20 to produce an organic EL element.

  The lighting display of the obtained organic EL element was confirmed by connecting and applying the first electrode 2 and the second electrode 7 of the display part of the obtained organic EL element to a power source.

  The minimum luminance required for the image display device is 1000 cd, but when the obtained organic EL element was driven, the area where 1000 cd could be uniformly lit in the pixel was 80% of the light emitting pixel. .

  After forming the interlayer 4, the thick film portion of the interlayer 4 was removed by exposure to toluene vapor. Other conditions are the same as in the first embodiment.

  The lighting display of the obtained organic EL element was confirmed by connecting and applying the first electrode 2 and the second electrode 7 of the display part of the obtained organic EL element to a power source.

  When the obtained organic EL element was driven, the area where 1000 cd could be uniformly lit in the pixel was 80% of the light emitting pixel.

[Comparative example]
After the interlayer 4 was formed, the thick film was not removed at all using an inorganic solvent, an organic solvent, or a mixed solution thereof. Other conditions are the same as in the first embodiment.

  The lighting display of the obtained organic EL element was confirmed by connecting and applying the first electrode 2 and the second electrode 7 of the display part of the obtained organic EL element to a power source.

  Furthermore, when the obtained organic EL element was driven, the area where 1000 cd could be uniformly lit in the pixel was 50% of the light emitting pixel.

  According to the organic EL elements according to Examples 1 and 2 of the present invention, the pixels were able to emit light uniformly by removing the thick portion formed in the vicinity of the partition wall 8 of the interlayer 4.

DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... 1st electrode, 3 ... Carrier injection layer, 4 ... Interlayer, 5 ... Organic light emitting layer, 5R ... Light emitting medium layer (red organic light emitting layer), 5G ... Light emitting medium layer (green organic light emitting layer)
5B: Light emitting medium layer (blue organic light emitting layer), 7 ... Second electrode, 8 ... Partition, 9 ... Sealing body, 10 ... Sealing resin, 100 ... Organic EL element, 200 ... Organic EL element with 3 pixels

Claims (7)

Prepare the board
Forming a first electrode on the substrate;
Forming a partition wall disposed between the plurality of first electrodes and projecting over an end of the first electrode;
The interlayer of the plurality of light emitting medium layer comprising the organic light-emitting layer was formed by a wet coating method in the vicinity of the partition wall of the upper first electrode and the projecting,
Wherein curing the interlayer on the first electrode, wherein in the vicinity of the partition wall of the protruding such that a portion of the interlayer is uncured, the surface opposite to the the formation of the interlayer surface Heated,
Removing the uncured portion of the interlayer,
The second electrode is formed on the interlayer,
The method for manufacturing an organic EL device, characterized in that said partition wall which protrudes form the following height 2μm or 0.5 [mu] m, the inter-layer is formed by the wet coating method so as to cover the partition wall to the overhang. The method for manufacturing an organic EL device according to claim 1 in which the temperature during the firing of processing the interlayer is characterized in that at 0.99 ° C. or higher 250 ° C. or less. The method for manufacturing an organic EL device according to claim 1 or claim 2, wherein the time for calcination treatment the interlayer is less than 30 minutes than 10 minutes. Any of claims 1 to 3, characterized in that removed by flushing the thick places of the inter-layer formed in the vicinity of the partition wall of the protruding inorganic solvent, an organic solvent or a mixture of these solutions The manufacturing method of the organic EL element of description. Thick places an inorganic solvent of the inter-layer formed in the vicinity of the partition wall of the protruding of claims 1 to 3, characterized in that the removal by exposure to the vapor of an organic solvent or a mixture of these solutions The manufacturing method of the organic EL element in any one. The organic EL element characterized in that it is formed by using the manufacturing method of the organic EL device according to any one of claims 1 to 5. Image display device characterized by having an organic EL element formed using a method of manufacturing an organic EL device according to any one of claims 1 to 5.