JP2013084553A - Organic el element and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL element which improves the flatness in picture elements and reduces local burdens on a luminescent material thereby achieving long life, and to provide a manufacturing method of the organic EL element.SOLUTION: An organic EL element according to this invention includes: a base material; a first electrode layer which is formed on the base material and has multiple sections respectively corresponding to multiple picture elements; a first partition wall formed so as to cover peripheral parts of the respective sections of the first electrode layer; an insulation layer which is formed on the first electrode layer and is provided with multiple through holes respectively corresponding to the picture elements; a second electrode layer which is formed on the insulation layer and electrically connects with the first electrode layer through the respective through holes; an organic light emitting medium layer formed on the second electrode layer; a third electrode layer formed on the organic light emitting medium layer; and a sealing layer covering the third electrode layer. The second electrode layer in each picture element and the organic light emitting medium layer in each picture element have recessed surface shapes.

Description

  The present invention relates to an organic EL device expected to be widely used as a flat panel display used in a mobile terminal such as a television, a personal computer monitor, a mobile phone, a surface emitting light source, an illumination, a light emitting advertising body, and the like. Regarding the method.

  An organic EL display using an organic EL element as a pixel is expected as a flat panel display replacing a cathode ray tube or a liquid crystal display because of advantages such as a wide viewing angle, a high response speed, and low power consumption.

  An organic EL element has a structure in which an organic light emitting medium layer is sandwiched between two electrode layers, at least one of which has translucency, and an organic light emitting medium is applied by applying a voltage between both electrodes and causing a current to flow. A self-luminous display element that emits light in a layer. However, in order to emit light efficiently, it is important to control the film thickness of the organic light-emitting medium layer. Furthermore, in order to make this a display, it is necessary to pattern with high definition.

  The organic light emitting material used for the organic light emitting medium layer includes a low molecular material and a polymer material. When using low molecular weight materials, a thin film is generally formed on a substrate by resistance heating vapor deposition (vacuum vapor deposition) or the like, and this thin film is patterned using a fine pattern mask to form an organic light emitting medium layer. To do. However, this method has a problem that the larger the substrate is, the more difficult it is to obtain patterning accuracy.

  Therefore, recently, there is a method in which a polymer material is used as an organic light emitting material, a coating ink solution is prepared by dissolving the organic light emitting material in a solvent, and then a thin film is formed by applying this to a substrate by a wet coating method. Attempts are being made. As the wet coating method, there are a spin coating method, a bar coating method, a protruding coating method, a dip coating method, etc., but high-definition patterning or three colors of red (R), green (G), and blue (B) Therefore, it is considered difficult to form a thin film by pattern printing using a printing method that is good at coating patterning.

  Further, among various printing methods, a glass substrate is often used as a substrate in organic EL elements and displays, so that a method using a hard metal printing plate used in a gravure printing method is not suitable. For this purpose, printing methods using elastic rubber printing plates, offset printing methods using rubber printing blankets, and photosensitive resin plates based on elastic rubber and other resins are used. The letterpress printing method used is employed. Specifically, as these printing methods, a pattern printing method by offset printing (see Patent Document 1), a pattern printing method by letterpress printing (see Patent Documents 2 and 3), and the like are known.

  On the other hand, it is known that viscous inks, thixotropic inks, or liquid inks used in letterpress printing methods have optimum viscosity and surface tension. Especially, liquid inks include thickeners. It is common to add a viscosity modifier, a surfactant for adjusting the surface tension, and the like.

  When an electronic material is printed, there are cases where the ink physical properties are largely restricted, such as the solubility of the material being limited or the impurities being hated.

  In particular, when an organic light emitting material is printed by a printing method to form a film, the organic light emitting material is printed by dispersing or dissolving in a solvent such as water, alcohol, other organic solvents, and a binder resin as necessary. Inked as an ink liquid for coating.

  In the case where an organic light emitting material is formed into a pattern and driven as an organic light emitting element, the durability of the element is preferably higher when the film formed of the organic light emitting material has a higher purity. Therefore, the thickener remaining in the film of the organic light emitting material cannot be added because it causes a decrease in purity. For this reason as well, the adjustable range of various physical properties of the organic light emitting material ink liquid necessary for obtaining the ink transferability of the printed matter and the stability of the pattern shape is limited.

  Because of the above reasons and the low solubility of the organic light emitting material, only a part of the aromatic solvent can be used as the solvent, and the selection range of the ink is not so large.

  In addition, when an organic light emitting material is applied to a pixel by a wet coating method, the coating liquid forms a meniscus on the partition wall that separates the pixel, so that the film thickness in the vicinity of the partition wall becomes extremely thick, and only the central portion of the pixel is normal. The phenomenon that light emission and the light emission area become narrow occurs. In this case, since the region that normally shines becomes narrow, it is necessary to pass a larger amount of current in order to obtain the overall brightness of the display. However, the load on the central portion of the pixel increases, leading to a significant reduction in luminance life. In particular, when a high-definition display having a small pixel width of 150 ppi or more is manufactured, the thickened region in the vicinity of the partition wall is relatively large due to meniscus formation. As a result, the luminance life is significantly shortened.

  Also, the color of light that can be extracted to the outside changes due to the phenomenon of interference with the reflected light of the metal electrode. However, when the film thickness in the pixel is not uniform, it becomes difficult to control the color of the entire panel. .

  Since it is difficult to control the ink properties for the reasons described above, as a countermeasure, ink jet printing or the like is performed to change the wettability of the partition walls and suppress the formation of meniscus. However, this method increases the number of processes and increases the capital investment for the plasma apparatus and the like. Further, when the organic light emitting medium layer is multilayered, the process margin is narrowed, and the difficulty of the process for flattening is increased.

  Therefore, a technique for making the surface of the anode curved in order to increase the luminous efficiency of the organic light emitting layer is known. If a shape corresponding to the organic light emitting material is formed in advance before the organic light emitting material is applied, it is expected that the film thickness difference in the pixel of only the organic light emitting material can be reduced. That is, improvement is expected by forming a concave curved surface that is recessed centering around the pixel center. For the formation of this structure, a method is adopted in which a concave curved portion is formed by etching a base material, and an anode, a hole injection layer, a light emitting layer, and a cathode are sequentially laminated thereon (Patent Documents 4 and 4). 5).

  On the other hand, when forming a concave shape by etching, there is a concern that the capital investment is large and the surface of the etching process is not smooth enough to adversely affect the shape of the anode formed on the substrate. Furthermore, since the smoothness is insufficient, there is a concern that a short circuit may occur between the anode and the cathode.

JP 2001-93668 A JP 2001-155858 A JP 2001-155861 A JP 2005-174717 A JP 2010-50107 A

  An object of the present invention is to provide a longer-life organic EL element and a method for manufacturing the same by improving the flatness of the organic light-emitting medium layer itself and reducing the load on the local light-emitting material.

  The present invention relates to an organic EL element having a plurality of pixels. The organic EL device according to the present invention includes a base material, a first electrode layer formed on the base material and having a plurality of sections corresponding to each of the plurality of pixels, and a peripheral portion of each of the sections of the first electrode layer. A first partition formed so as to cover the first electrode layer, an insulating layer formed on the first electrode layer and provided with a plurality of through holes corresponding to each of the pixels, and formed on the insulating layer, each of the through holes being A second electrode layer electrically connected to the first electrode layer, an organic light emitting medium layer formed on the second electrode layer, a third electrode layer formed on the organic light emitting medium layer, A sealing layer covering the three electrode layers. The second electrode layer in each pixel and the organic light emitting medium layer in each pixel have a concave shape.

  Moreover, this invention relates to the manufacturing method of the organic EL element which has said structure. The method for producing an organic EL element according to the present invention includes a step of forming a first electrode layer having a plurality of sections corresponding to each of a plurality of pixels on a substrate, and a peripheral edge of each section of the first electrode layer. Forming a first partition so as to cover the part, forming an insulating layer provided with a plurality of through holes corresponding to each of the pixels on the first electrode layer, and forming a through hole on the insulating layer. Forming a second electrode layer electrically connected to the first electrode layer through each of them, forming an organic light emitting medium layer on the second electrode layer, and a third electrode on the organic light emitting medium layer A step of forming a layer and a step of forming a sealing layer covering the third electrode layer, and the insulating layer is formed by a wet coating method or a printing method.

  According to the present invention, it is possible to provide a longer-life organic EL element and a method for manufacturing the same by improving the flatness of the organic light emitting medium layer and reducing the load on the local light emitting material.

Schematic cross-sectional view of an organic EL device according to an embodiment of the present invention BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional enlarged schematic diagram of the through-hole part of the organic EL element which concerns on embodiment of this invention, (a) is a figure which shows the state after formation of the insulating layer provided with the through-hole, (b) is 2nd electrode layer formation Figure showing the state after

  Hereinafter, an example of the organic EL element of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiment.

  An object of this invention is to obtain the film thickness uniformity in a pixel at the time of printing an electronic material as a display by the relief printing method.

  FIG. 1 is a schematic cross-sectional view showing an organic EL element according to an embodiment of the present invention. The organic EL element shown in FIG. 1 includes a base material 10, a first electrode layer 11, an insulating layer 12, a second electrode layer 14, an organic light emitting medium layer 15, and a third electrode layer 16. A through hole 13 is formed in the insulating layer 12. The organic light emitting medium layer 15 includes a hole transport layer, an organic light emitting layer, and an electron injection layer.

In the organic EL element according to the present embodiment, the electrode substrate 10 is used. The electrode base material 10 may be any material as long as the first electrode layer 11 described later is formed on a base material made of a plastic film such as glass, quartz, polyethersulfone, or polycarbonate.
Hereinafter, an example using a driving substrate in which a thin film transistor (TFT) is formed on a base material will be described.

  A well-known thing can be utilized as a 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, a bottom 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. As a method for forming these active layers, for example, amorphous silicon is laminated by plasma CVD, ion doping, amorphous silicon is formed by LPCVD using SiH ₄ gas, and amorphous silicon is formed by solid phase growth. After obtaining polysilicon by crystallization, an ion doping method using an ion implantation method, an amorphous silicon is formed by an LPCVD method using Si ₂ H ₆ gas, and a PECVD method using SiH ₄ gas, and an excimer laser After annealing with a laser such as crystallizing amorphous silicon to obtain polysilicon, a method of ion doping by ion doping method (low temperature process), polysilicon is laminated by low pressure CVD method or LPCVD method, and 1000 ° C. or more Thermal oxidation Forming a gate insulating film Te, the 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, SiO ₂ formed by PECVD method, LPCVD method, etc .; SiO ₂ 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.

  In the organic EL element, the drain electrode of the thin film transistor and the first electrode layer 11 of the organic EL element are electrically connected so that the thin film transistor functions as a switching element of the organic EL element. The connection between the drain electrode of the thin film transistor and the first electrode layer 11 of the organic EL element is made through a connection wiring formed in a contact hole that penetrates the planarization film.

  The first electrode layer 11 is partitioned by the first partition wall 17 and becomes a pixel electrode corresponding to each pixel. As the material of the first electrode layer 11, a material having a high work function such as ITO is preferably selected. Metal composite oxides such as ITO (indium tin composite oxide), indium zinc composite oxide, and zinc aluminum composite oxide Alternatively, a metal material such as gold or platinum, or a single layer or a laminate of fine particle dispersion films in which fine particles of these metal oxides or metal materials are dispersed in an epoxy resin or an acrylic resin can be used. In addition, when the first electrode layer 11 needs to have hole injection property and reflectivity as in the case of a top emission type organic EL element, an ITO film is laminated on a metal material such as Ag or Al. do it. The optimum film thickness of the first electrode layer 11 varies depending on the element configuration of the organic EL element, but it is not less than 100 mm and not more than 10,000 mm, more preferably not more than 3000 mm, regardless of single layer or stacked layers.

  As a formation method of the first electrode layer 11, depending on the material, dry film formation methods such as resistance heating evaporation method, electron beam evaporation method, reactive evaporation method, ion plating method, sputtering method, gravure printing method, A wet film formation method such as a screen printing method can be used.

  The first partition 17 is formed so as to partition the light emitting region corresponding to the pixel. In general, in an active matrix drive type display device, a first electrode layer 11 is formed for each pixel. In order to increase the area of each pixel as much as possible, the most preferable shape of the first partition wall 17 formed so as to cover the end of the first electrode layer 11 is a lattice shape that divides the first electrode layer 11 by the shortest distance. is there.

  As a method for forming the first partition wall 17, as in the conventional method, an inorganic film is uniformly formed on a substrate, masked with a resist, and then dry-etched, or a photosensitive resin is laminated on the substrate. And a method of forming a predetermined pattern by photolithography. If necessary, a water repellent can be added, or plasma or UV can be irradiated to impart liquid repellency to the ink after formation.

  The preferred height of the first partition wall 17 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 first partition wall 17 exceeds 10 μm, formation and sealing of the counter electrode will be hindered. If the height of the first partition wall 17 is less than 0.1 μm, the end portion of the first electrode layer 11 cannot be covered, or the adjacent pixels are short-circuited or mixed when the light emitting medium layer is formed.

  The insulating layer 12 is formed by spin-coating an insulating material having photosensitivity and light transmittance on a base material. When the material is applied by the wet coating method in this way, the coating liquid forms a meniscus in the pixels separated by the partition walls. At this time, since the force attracting the liquid molecules of the material is stronger in the partition wall than in the material, the film thickness in the vicinity of the partition wall becomes extremely thick, and a concave curved surface shape can be formed naturally. A concave curved surface shape is formed in the same manner in the printing method. Here, a coating liquid of an insulating material is applied onto the partition walls by spin coating, but there is a difference that the coating method does not apply up to the partition walls, but there is no difference in characteristics. Since the insulating layer 12 needs to be thinner than the first partition wall 17 in order to form a concave curved surface shape, it is preferably 0.1 μm or more and less than 2 μm.

  When a high-definition display having a small pixel width of 150 ppi or more is manufactured, a thickened region due to meniscus formation in the vicinity of the partition wall becomes relatively large. Since the size of the pixel opening greatly affects the shape of the insulating layer, it is necessary to determine the optimum forming conditions such as the viscosity of the coating liquid of the insulating layer according to the size of the pixel opening.

Thereafter, the through hole 13 is formed by photolithography. Since the through hole 13 needs to be formed so that the first electrode layer 11 and the second electrode layer 14 can conduct, the length of the through hole 13 is equal to the thickness of the insulating layer 12 in the penetrating portion. . The through hole 13 does not have a reverse taper shape in which the inner diameter increases toward the first electrode layer 11 in order to achieve conduction, but is in a columnar shape or an order in which the inner diameter decreases toward the first electrode layer 11. A taper shape is preferable. The inner diameter of the through hole 13 is not limited as long as it is large enough to allow conduction between the electrodes, but if it is too large, the flatness in the pixel is affected, so that it is preferably 2 μm or more and less than 30 μm.
Furthermore, the through hole is not limited to a circular shape, and may be a square shape. Further, a plurality of through holes may be provided in the insulating layer 12 as long as the concave curved surface shape of the insulating layer 12 can be maintained. In this way, by providing a large number of through-holes to a pixel that is generally square, a current flowing from the through-hole can be easily spread to the second electrode by providing a large number of squares and crosses. The current to the light emitting medium layer 15 can also flow from not only around the through hole but also from the entire second electrode surface.

  Here, the definition of the flat rate will be described. The definition of the flatness ratio in the pixel of the organic EL element is such that when the film thickness in the pixel in the short side direction passing through the center of the pixel is viewed, the height difference is 10 nm as a region having a small difference in film thickness of the organic light emitting layer. The width of the region Y can be divided by the pixel width X (in-pixel flatness percentage = the width of the region Y with a small height difference (the height difference of 10 nm) / pixel width X × 100). In other words, the flatness here refers to the ratio of the width of the continuous region Y whose maximum height difference is within 10 nm in the pixel width X in the short side direction passing through the center of the pixel.

  The second electrode layer 14 is formed in a predetermined pattern using the same material and forming method as the first electrode layer 11. The second electrode layer 14 is electrically connected to the first electrode layer 11 through the through hole 13. If the shape of the edge of the through hole 13 is a right angle, the second electrode layer 14 needs to have a film thickness equal to or greater than the length of the through hole 13, but the through hole 13 faces the first electrode layer 11. The thickness of the second electrode layer 14 is not particularly limited as long as the diameter is a forward tapered shape.

  Next, the formation of the insulating layer 12 lowers the first partition wall 17 that separates the pixels, and there is a risk of color mixture with adjacent pixels, and also covers the end of the second electrode layer 14 to prevent a short circuit. The second partition wall 18 is formed so as to partition the light emitting region corresponding to the pixel, like the first partition wall 17. In general, in an active matrix drive type display device, a second electrode layer 14 is formed for each pixel. In order to increase the area of each pixel as much as possible, the most preferable shape of the second partition wall 18 is The second electrode layer 14 has a lattice shape that divides the electrode layer 14 by the shortest distance.

  As a method of forming the second partition wall 18, similarly to the first partition wall 17, a method in which an inorganic film is uniformly formed on a substrate, masked with a resist, and then dry etching is performed, or a photosensitive resin is formed on the substrate. And a method of forming a predetermined pattern by photolithography. If necessary, a water repellent can be added, or plasma or UV can be irradiated to impart liquid repellency to the ink after formation.

  The preferred height of the second partition wall 18 is not less than 0.1 μm and not more than 10 μm, and more preferably not less than 0.3 μm and not more than 2 μm. If the height of the second partition wall 18 exceeds 5 μm, the formation and sealing of the counter electrode may be hindered, or the effect aimed at flattening the organic light emitting medium layer may be reduced by forming a concave curved surface shape. . On the other hand, if the height of the second partition wall 18 is less than 0.1 μm, the end of the second electrode layer 14 cannot be covered, or the adjacent pixels are short-circuited or mixed when forming the organic light emitting medium layer. End up.

  The organic light emitting medium layer 15 can be formed of a single layer film containing a light emitting substance or a multilayer film. Examples of the configuration in the case of forming a multilayer film include a hole transport layer and an electron transporting light emitting layer, or a two layer structure of a hole transporting light emitting layer and an electron transport layer, a hole transport layer, a light emitting layer, and an electron. A three-layer structure consisting of a transport layer. Furthermore, if necessary, the hole (electron) injection function and the hole (electron) transport function are separated, or a layer that blocks the transport of holes and electrons is inserted. It is more preferable to further increase the number of layers.

  Examples of hole transport materials include polyaniline, polythiophene, polyvinyl carbazole, polymer hole transport materials such as a mixture of poly (3,4-ethylenedioxythiophene) and polystyrene sulfonic acid, polythiophene oligomer materials, and other existing materials You can choose from hole transport materials.

  In the case of a polymer EL element, it is preferable to form an interlayer layer on the hole transport layer. Examples of materials used for the interlayer layer 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 can be dissolved or dispersed in a solvent and formed using various coating methods such as spin coating or letterpress printing.

  Examples of the light-emitting material include polymer materials such as polyfluorene, polyparaphenylene vinylene, polythiophene, and polyspiro, materials obtained by dispersing or copolymerizing the low-molecular materials in these polymer materials, and other existing fluorescent light-emitting materials and phosphorescent light-emitting materials. Materials can be used.

  Examples of electron transport materials include 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (1-naphthyl) -1 , 3,4-oxadiazole, oxadiazole derivatives, bis (10-hydroxybenzo [h] quinolinolato) beryllium complexes, triazole compounds, and the like can be used. Alternatively, these electron transport materials may be used as an electron injection layer by doping a small amount of alkali metal or alkaline earth metal having a low work function such as sodium, barium, or lithium.

  The film thickness of the organic light-emitting medium layer 15 is 1000 nm or less, preferably about 50 to 200 nm, even when formed by a single layer or a stacked layer.

  As a method of forming the organic light emitting medium layer 15, depending on the material, a vacuum deposition method, a coating method such as slit coating, spin coating, spray coating, nozzle coating, flexo, gravure, micro gravure, intaglio offset, printing method, An ink jet method or the like can be used. Among these, polymer materials that can be formed using a printing method can be formed into a large area by dissolving or stably dispersing in a solvent to form an ink, and an organic EL element using a low molecular material. There is an advantage that it is low-cost compared with the manufacture of

  The third electrode layer 16 may have at least a role as an electron-injecting cathode, and may be an alkali metal or alkaline earth metal such as Li, Ba, or Ca, and a stable metal film such as Al or Ag. A laminated film is used. In the case of a top emission type organic EL element, it is necessary to also serve as a transparent electrode. Therefore, as an electron injecting cathode, an alkali metal or alkaline earth such as Li, Ba, Mg, or Ca having a low work function is used. Similar metals and oxides and fluorides of these metals can be used. Although these materials are excellent in electron injecting property, they are poor in stability. Therefore, it is more preferable to use a laminated film or an alloy film with a metal having excellent stability such as Al or Ag.

  As a method for forming the third electrode layer 16, 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 may be selected depending on the material. Moreover, there is no restriction | limiting in particular in the thickness of the 3rd electrode layer 16, but it can use by about 10 nm or more and 1000 nm or less. In the case of a top emission type EL element, an alkali metal such as Ba may be about 5 nm, a stable metal such as Al may be about 10 nm, and a transparent electrode such as ITO may be laminated to about 100 nm to reduce the resistance.

  The sealing structure of the organic EL element is not particularly limited. For example, cap sealing using a sealing base material 20 made of a glass cap, a passivation film and an adhesive layer 19, and a sealing base material 20 made of a glass base material. There are solid seals used. The passivation layer includes metal oxides such as silicon oxide and aluminum oxide, metal fluorides such as aluminum fluoride and magnesium fluoride, metal nitrides such as silicon nitride, aluminum nitride and carbon nitride, and metal acids such as silicon oxynitride. A laminated film of a metal carbide such as nitride or silicon carbide, and a polymer resin film such as an acrylic resin, an epoxy resin, a silicone resin, or a polyester resin may be used as necessary. In particular, it is preferable to use silicon oxide, silicon nitride, or silicon oxynitride from the viewpoint of barrier properties and transparency. Furthermore, a laminated film or a gradient film with a variable film density may be used depending on the film forming conditions. . Further, these may be provided with a color conversion layer, a color filter layer, a light extraction layer, or the like as required.

As a method for forming the passivation layer, 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 CVD method can be used depending on the material. It is preferable to use a CVD method in terms of translucency. As the CVD method, a thermal CVD method, a plasma CVD method, a catalytic CVD method, a VUV-CVD method, or the like can be used. In addition, as a reaction gas in the CVD method, a gas such as N ₂ , O ₂ , NH ₃ , H ₂ , N ₂ O is added to an organic silicon compound such as monosilane, hexamethyldisilazane (HMDS), or tetraethoxysilane. It may be added as necessary. For example, the density of the film may be changed by changing the flow rate of silane, and hydrogen or carbon may be contained in the film by the reactive gas used. The film thickness of the sealing layer varies depending on the electrode step of the organic EL element, the height of the partition walls of the substrate, the required barrier characteristics, and the like, but generally about 10 nm to 10,000 nm is generally used.

  As the material of the adhesive layer 19, a known adhesive resin can be used. For example, a photo-curable adhesive resin such as an epoxy resin, an acrylic resin, or a silicone resin, a thermosetting adhesive resin polyethylene, polypropylene, or the like. It is possible to use a thermoplastic adhesive resin made of an acid-modified product. The adhesive layer 19 can be mixed with spherical or rod-like spacers made of glass or resin for gap control as required.

As a method for forming the adhesive layer 19, depending on the material and pattern, a coating method such as spin coating, spray coating, flexo, gravure, micro gravure, intaglio offset, printing method, ink jet method, dispenser application, nozzle ejection, transfer Method, laminating method and the like can be used.

  The step of bonding the electrode base material 10 and the sealing base material 20 through the adhesive layer 19 is performed in a vacuum so that the adhesive layer 19 does not contain oxygen and moisture that cause deterioration of the organic EL element, or Perform in an inert gas atmosphere. When an inert gas is used, a rare gas such as argon can be used, but nitrogen is preferably used for ease of handling and economical reasons.

  Examples of the present invention and comparative examples will be described below, but the present invention is not limited to these examples.

<Example>
First, a first electrode layer 11 made of an ITO film (400 nm) was formed on a base material 10 made of parallel flat glass, which is a transparent substrate, using a sputtering method, a photolithography method, and an etching method.

  Next, a first partition was formed. Specifically, a positive resist ZWD6216-6 manufactured by Nippon Zeon Co., Ltd. was formed on the entire surface of the substrate with a spin coater to a thickness of 1 μm, and then the first partition wall 17 was formed using a photolithography method. The light emitting region was partitioned by the first partition wall 17.

  Next, the insulating layer 12 was formed. Specifically, a resin solution composed of an ultraviolet curable transparent resin containing an acrylic monomer is spin-coated on the first electrode layer 11 so that the finished film thickness is 0.5 μm, and after drying under reduced pressure, Heated at 90 ° C. for 90 seconds. Thereafter, light having a high pressure mercury lamp as a light source was irradiated at a dose of 100 mJ / cm 2 so as to form a desired pattern. Then, after developing for 30 seconds with an alkali developer, baking was performed at 230 ° C. for 40 minutes. In this way, an insulating layer 12 having a through hole 13 having a diameter of 3 μm and a tapered edge shape at the center of the pixel was obtained. At this time, since the resin solution is applied to the aperture pixels, the wet liquid forms a meniscus on the partition walls separating the pixels, so that the film thickness in the vicinity of the partition walls is increased, and the pixel opening portions have a concave shape.

  Subsequently, the second electrode layer 14 was formed. Specifically, an ITO film (400 nm) is formed using a sputtering method, a photolithography method, and an etching method, and the second electrode layer 14 is formed, and the first electrode layer 11 and the second electrode layer 14 are electrically connected through the through hole 13. I let you.

  Then, the 2nd partition 18 was formed in the shape which divides a pixel. Specifically, a positive resist ZWD6216-6 manufactured by Nippon Zeon Co., Ltd. was formed on the entire surface of the substrate with a spin coater to a thickness of 1 μm, and then the second partition wall 18 was formed using a photolithography method.

  Next, the organic light emitting medium layer 15 was formed. Specifically, a mixture (20 nm) of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid is used for the hole transport layer, and poly [2-methoxy-5- ( Using 2'-ethyl-hexyloxy) -1,4-phenylene vinylene] (MEHPPV) (100 nm), each was patterned using a relief printing method to obtain an organic light emitting medium layer with a flatness of 83%.

  Next, the third electrode layer 16 was formed. Specifically, a Ba film (5 nm) and an Al film (200 nm) were stacked using a vapor deposition method. Next, for sealing, an adhesive 15 (photo-curing epoxy adhesive) and a sealing material 16 (glass base material) were laminated in order to manufacture an organic EL element according to the example.

  The organic EL device according to this example emitted light uniformly to the periphery of the pixel, greatly increased the light emitting area, and improved the lifetime by 30% compared to the conventional product.

<Comparative Example 1>
Although formed using the same method as in the example, the insulating layer 12 and the second electrode layer 14 provided with the through hole 13 were not formed, and an organic EL device was manufactured through other steps.

  The flatness of the organic light emitting medium layer of the organic EL element according to Comparative Example 1 was 42%. In addition, the light emitting area when light is emitted is narrower than that of the organic EL element according to the embodiment, and the portion where the organic light emitting layer with a large film thickness around the pixel is difficult to flow, and the light emission is weakened. confirmed. That is, a clear light emission difference was caused by the flatness.

<Comparative example 2>
Although it formed using the method similar to an Example, the 2nd partition 18 was not formed but the organic EL element was manufactured by performing other processes. The flatness of the organic light emitting layer of the organic EL element according to Comparative Example 2 was 60% in part, and an improvement in flatness was observed. However, the first partition 17 alone is not sufficient to prevent color mixing, and many color mixing occurs, causing a problem in display characteristics.

<Comparative Example 3>
The organic EL device was manufactured using the same method as in the example, but the diameter of the through hole 13 was 40 μm and occupied 60% or more of the opening width of the pixel.

  The flatness of the organic light emitting medium layer of the organic EL element produced as described above was 50%. Since the diameter of the through hole 13 occupies most of the opening width of the pixel, a necessary concave curved surface shape cannot be obtained, and as a result, a great improvement in flatness cannot be obtained.

<Comparative example 4>
The organic EL device was manufactured using the same method as in Example, but the through-hole 13 was as long as 5 μm.

  The flatness of the organic light emitting medium layer of the organic EL element produced as described above was 42%. The length of the through hole 13 of 5 μm is equal to the film thickness of the insulating layer 12 at the place where the through hole 13 is formed. Therefore, in order to increase the length (depth) of the through hole 13, it is necessary to form the insulating layer 12 having a thickness corresponding to the length. In this case, the insulating layer 12 is formed by the first partition wall. It becomes thicker than the height of 17 (because it is the same condition as Example 1 and is 1 μm). Therefore, in Comparative Example 4, the shape of the pixel remained flat, and no improvement in the flatness of the organic light emitting medium layer was obtained.

  INDUSTRIAL APPLICATION This invention can be utilized for the organic EL element used for a flat panel display, a surface emitting light source, illumination, etc., and its manufacturing method.

DESCRIPTION OF SYMBOLS 10 ... Base material 11 ... 1st electrode layer 12 ... Insulating layer 13 ... Through-hole 14 ... 2nd electrode layer 15 ... Organic luminescent medium layer 16 ... 3rd electrode layer 17 ... 1st partition 18 ... 2nd partition 19 ... Adhesive layer 20 ... Sealing substrate

Claims (8)

An organic EL element having a plurality of pixels,
A substrate;
A first electrode layer formed on the substrate and having a plurality of sections corresponding to each of the plurality of pixels;
A first partition formed so as to cover each peripheral edge of the section of the first electrode layer;
An insulating layer formed on the first electrode layer and provided with a plurality of through holes corresponding to each of the pixels;
A second electrode layer formed on the insulating layer and electrically connected to the first electrode layer through each of the through holes;
An organic light emitting medium layer formed on the second electrode layer;
A third electrode layer formed on the organic light emitting medium layer;
A sealing layer covering the third electrode layer,
The organic EL element in which the second electrode layer in each pixel and the organic light emitting medium layer in each pixel have a concave shape.   The organic EL element according to claim 1, wherein the most concave portion of the concave shape is a center portion of the pixel. The second electrode layer is partitioned into a plurality of regions corresponding to each of the plurality of pixels on the first partition wall,
And a second partition formed on the first partition so as to extend along the first partition and covering a peripheral portion of each of the regions of the second electrode layer. The organic EL device according to claim 1.   The organic EL element according to claim 1, wherein the insulating layer provided with the through hole has light transmittance.   The organic EL element according to claim 1, wherein an insulating layer provided with the through hole has photosensitivity.   The organic EL element according to claim 1, wherein a diameter R of the through hole satisfies 2 μm <R <30 μm.   The organic EL element according to claim 1, wherein a length T of the through hole satisfies 0.1 μm <T <2 μm. It is a manufacturing method of the organic EL element in any one of Claims 1-6,
Forming a first electrode layer having a plurality of sections corresponding to each of the plurality of pixels on a substrate;
Forming the first partition so as to cover the peripheral edge of each of the sections of the first electrode layer;
Forming the insulating layer provided with a plurality of through holes corresponding to each of the pixels on the first electrode layer;
Forming a second electrode layer electrically connected to the first electrode layer via each of the through holes on the insulating layer;
Forming the organic light emitting medium layer on the second electrode layer;
Forming the third electrode layer on the organic light emitting medium layer;
Forming the sealing layer covering the third electrode layer,
A method for producing an organic EL element, wherein the insulating layer is formed by a wet coating method or a printing method.