JP2011210614A - Organic el element and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL display and a method of manufacturing the same, which suppresses a leak current and also suppresses disconnection of an electrode formed on an organic film, by devising a shape of a barrier rib for partitioning a pixel.SOLUTION: The barrier rib 103 which partitions a pixel electrode 102 and has an insulation property is arranged on a substrate 101. The barrier rib 103 has at least two layers of a first barrier rib part 103A and a second barrier rib part 103B on the first barrier rib part 103A. The first barrier rib part 103A has a vertical or invert taper shape on the substrate 101. The second barrier rib part 103B has a bottom part of the second barrier part 103B having a width equal to a width of an upper part of the first barrier rib part 103A.

Description

  The present invention relates to a display device technique, and more particularly to an organic EL element (organic electroluminescence element) and a method for manufacturing the same.

  In the organic EL element, by applying a voltage to the conductive light emitting medium layer, electrons and holes injected in the organic light emitting layer in the light emitting medium layer are recombined. The organic light emitting molecules in the organic light emitting layer are once excited by the recombination energy, and then return from the excited state to the ground state. The organic EL element emits light by taking out the energy released at this time as light. In order to apply a voltage to the organic light emitting medium layer, a pixel electrode and a counter electrode are provided on both sides of the light emitting medium layer, and at least one of the electrodes has a light transmitting property in order to extract light from the light emitting layer to the outside. Have. As an example of the structure of such an organic EL element, a light-transmitting pixel electrode, a light emitting medium layer, and a counter electrode are sequentially stacked on a light-transmitting substrate. Here, there is an embodiment in which the pixel electrode formed on the substrate is used as an anode, and the counter electrode formed on the light emitting medium layer is used as a cathode.

  In addition to increasing the luminous efficiency, as an organic EL element, in addition to the hole transport layer and hole injection layer provided between the anode and the organic light emitting layer, electron transport between the organic light emitting layer and the cathode. In many cases, a layer and an electron injection layer are appropriately selected and provided. These hole transport layer, hole injection layer, electron transport layer, and electron injection layer are called carrier transport layers. The carrier transport layer, the organic light emitting layer, the hole blocking layer, the electron blocking layer, the insulating layer, and the like are collectively referred to as a light emitting medium layer.

  When the light emitting medium layer is configured as described above and each of the substances (referred to as a light emitting medium material) exhibiting each function is a low molecular compound, each layer is laminated by a vacuum evaporation method such as a resistance heating method. .

  On the other hand, there is an organic EL element (hereinafter referred to as a polymer organic EL element) using a polymer material as the organic light emitting layer. By dissolving or dispersing the polymer material in a solvent, the light emitting layer can be formed by a wet method such as a coating method or a printing method. Therefore, compared with the organic EL element using the above-mentioned low molecular weight material, there is an advantage that film formation under atmospheric pressure is possible and equipment cost is low.

  When manufacturing an image display device, an image is displayed by a large number of pixels arranged vertically and horizontally. For this purpose, it is necessary to selectively dispose a light emitting material, a hole injection material, or the like on the pixel electrode and form an independent organic EL element for each pixel. At that time, in order to uniformly distribute the material to each pixel and to uniformly emit light, a method of providing partition walls that partition each pixel in advance is generally used.

  Currently, methods for improving the film thickness distribution of the organic film by devising the shape of the partition structure are being actively studied. For example, there are a two-stage partition structure (Patent Document 1) (Patent Document 3), a reverse taper structure (Patent Document 2), and a kanji structure (Patent Document 3). The purpose of these is to suppress light emission unevenness due to the film thickness distribution that occurs when the film thickness of the hole transport layer formed on the anode is increased.

JP 2006-286309 A JP 2007-95630 A JP 2007-220656 A JP 2008-243545 A

  However, even when the film thickness is controlled, when a hole transport layer having high conductivity is used, a current that does not contribute to the light emission phenomenon (hereinafter referred to as a leakage current) flows in the direction of the partition wall, and the performance of the organic EL element is reduced. There is concern that it will decline. And in an image display device constituted by such an organic EL element, there is a problem that it is difficult to control a desired display when a leak current flows between adjacent pixels.

In order to solve such a problem, as described in Patent Document 4, a technique for suppressing leakage current by physically disconnecting the hole transport layer by a partition structure having a two-stage structure has been studied.
However, this method has a problem that the cathode may be disconnected at the same time due to the sharp edge of the first partition wall. In order to prevent disconnection, it is necessary to stack the cathode thicker by that amount, which causes deterioration of characteristics due to damage caused by a film forming process such as vapor deposition, tact down, and cost increase.

  The present invention has been made paying attention to the above points, and by devising the shape of the partition wall that partitions the pixel, the leakage current is suppressed and the disconnection of the electrode formed on the organic film is suppressed. An object of the present invention is to provide an organic EL display and a method for manufacturing the same.

In order to solve the above-described problems, the invention according to claim 1 of the present invention includes a pixel electrode, a counter electrode, and an organic light-emitting medium layer including a hole transport layer and an organic light-emitting layer on a substrate. Is an organic EL element formed so as to face each other,
On the substrate, partition walls having an insulating property are formed to partition the pixel electrode, and the partition wall includes at least a first partition wall portion and a second partition wall portion formed on the partition wall from the side closer to the substrate. Has two layers,
The wall surface of the first partition wall has an angle of 90 degrees or less than 90 degrees with the substrate surface,
The width of the bottom portion on the substrate side of the second partition wall portion is the same as or substantially the same as the width of the upper portion of the first partition wall portion.

Next, the invention described in claim 2 is characterized in that, with respect to the configuration described in claim 1, the first partition wall portion is an inorganic insulating material.
Next, the invention described in claim 3 is the structure described in claim 1 or 2, wherein the film thickness of the first partition wall portion is equal to the total film thickness of the organic light emitting medium layer or the organic light emission. It is characterized by being thicker than the total film thickness of the medium layer.

Next, in the invention described in claim 4, the pixel electrode is a transparent electrode with respect to the configuration described in any one of claims 1 to 3,
The hole transport layer is arranged closer to the pixel electrode than the organic light emitting layer.
Next, in the invention described in claim 5, the counter electrode is a transparent electrode with respect to the configuration described in any one of claims 1-4.
The hole transport layer is arranged closer to the pixel electrode than the organic light emitting layer.

Next, the invention described in claim 6 is an organic EL device in which a pixel electrode and a counter electrode are arranged to face each other on a substrate with an organic light emitting medium layer including a hole transport layer and an organic light emitting layer interposed therebetween. A method for manufacturing an element, comprising:
In preparation for a partition forming step of forming a partition for partitioning the pixel electrode on the substrate,
The partition wall forming step includes a first step of forming a first partition wall portion and a second step of forming a second partition wall portion on the first partition wall portion,
The wall surface of the first partition wall is formed so that the angle formed with the substrate surface is 90 degrees or less than 90 degrees,
The width of the bottom portion on the substrate side of the second partition wall portion is formed to be the same as or substantially the same as the width of the upper portion of the first partition wall portion.

Next, the invention described in claim 7 is characterized in that, in the configuration described in claim 6, the first partition wall portion is made of an inorganic insulating material.
Next, the invention described in claim 8 is directed to the configuration described in claim 6 or claim 7, wherein the film thickness of the first partition wall portion is equal to the total film thickness of the organic light emitting medium layer or the organic light emission. It is formed so as to be thicker than the total film thickness of the medium layer.

Next, in the invention described in claim 9, the pixel electrode is a transparent electrode with respect to the configuration described in any one of claims 6 to 8,
The hole transport layer is disposed closer to the pixel electrode than the organic light emitting layer.
Next, in the invention described in claim 10, the counter electrode is a transparent electrode with respect to the configuration described in any one of claims 6 to 8,
The hole transport layer is disposed closer to the pixel electrode than the organic light emitting layer.

  According to the present invention, the partition has at least two layers of the first partition and the second partition on the first partition, and the first partition is, for example, perpendicular to the substrate or inversely tapered. Provided in the shape. Furthermore, the second partition wall portion is provided with the same width at the bottom of the second partition wall portion as compared with the width of the upper portion of the first partition wall portion. As a result, it is possible to prevent disconnection of electrodes formed on the organic light emitting medium layer and leakage current to the partition walls.

That is, by forming the first partition wall so as to rise perpendicularly to the substrate or in an inversely tapered shape, the hole transport layer formed on the electrode can be physically disconnected, To prevent leakage current on the barrier ribs. As a result, a current flows only in the pixel electrode, and uneven light emission can be suppressed.
In addition, by providing the second partition wall portion with the same width as the upper portion of the first partition wall portion, the influence of the sharp edge of the first partition wall portion is suppressed and the disconnection of the electrode is prevented. Thus, an EL display device with no display failure and good EL characteristics can be manufactured.

  In particular, by providing the first partition wall with a thickness equal to or greater than the total thickness of the organic light emitting medium layer, the disconnection of the electrode formed on the organic light emitting medium layer and the leakage onto the partition are more reliably performed. It becomes possible to prevent current.

It is the cross-sectional schematic diagram which showed the organic electroluminescence display which concerns on embodiment of this invention. It is sectional drawing which concerns on embodiment of this invention. It is the cross-sectional schematic diagram which showed the organic electroluminescence display. 1 is a schematic view of a relief printing apparatus according to an embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. The drawings referred to in the following description of the embodiments are for explaining the configuration of the present embodiment, and the size, thickness, ratio of dimensions, etc. of the respective parts shown in the drawings are the same as those in the embodiment. It does not represent.

(Organic EL display device)
First. An organic EL display device using the organic EL element according to the present invention will be described.
FIG. 1 is a cross-sectional view of an organic EL display device for explaining an embodiment of the present invention.

  In the organic EL display device 100 of the present embodiment, the pixel electrode 102 and the counter electrode 107 are arranged to face each other on the substrate 101 with the organic light emitting medium layer 108 including the hole transport layer 104 and the organic light emitting layer 106 interposed therebetween. Is formed. That is, as shown in FIG. 1, the organic EL display device 100 includes a pixel electrode (anode) 102 provided for each pixel on a substrate 101, a partition wall 103 that partitions the pixels of the pixel electrode 102, and a pixel A hole transport layer 104 formed on the electrode 102, an interlayer 105 formed on the hole transport layer 104, an organic light emitting layer 106 formed on the interlayer 105, and an organic light emitting layer A counter electrode (cathode) 107 formed so as to cover the entire surface of 106 is formed. Further, a sealing body 109 is provided so as to cover the pixel electrode 102, the partition wall 103, the hole transport layer 104, the interlayer 105, the light emitting medium layer 108 including the organic light emitting layer 106, and the counter electrode 107.

  Here, the light emitting medium layer 108 is a layer disposed between the pixel electrode (anode) 102 and the counter electrode (cathode) 107. In the element of FIG. 1, the hole transport layer 104, the interlayer 105, and the organic light emitting layer 106 correspond to the light emitting medium layer 108. In addition, a layer such as a hole injection layer, an electron transport layer, or an electron injection layer may be added as the light emitting medium layer 108 as appropriate.

FIG. 2A and FIG. 2B are cross-sectional views of the stacked portion of the organic EL element in the present embodiment.
FIG. 2A shows an example of a bottom emission type organic EL element. In this example, a pixel electrode 102 made of a transparent electrode, a hole transport layer 104, an organic light emitting layer 106205, and a counter electrode 107 are laminated on a substrate 101 in this order. As long as the layers are stacked in this order, the inter layer 105 and other layers may be interposed between the layers. In the case of the bottom emission type, the counter electrode 107 is a light impermeable electrode, and the light emitted to the counter electrode 107 side is reflected by the counter electrode 107 and is externally transmitted from the pixel electrode 102 side which is a light transmissive electrode. To exit.

  FIG. 2B shows an example of a top emission type organic EL element. In this example, the reflective layer 207, the pixel electrode 102, the hole transport layer 104, the interlayer 105, the organic light emitting layer 106, and the counter electrode 107 made of a transparent electrode are stacked in this order on the substrate 101. Other layers may be interposed between the layers as long as they are laminated in this order. In the case of the p-emission type, the counter electrode 107 is a light-transmitting electrode, and light emitted to the pixel electrode 102 side is transmitted through the pixel electrode 102 and reflected by the reflective layer 207 to be emitted from the counter electrode 107 side to the outside. To do. On the other hand, the light emitted to the counter electrode 107 side is transmitted through the counter electrode 107 and emitted to the outside.

  In the following description, a bottom emission type organic EL element will be described as a representative, but the same applies to a top emission type in which the counter electrode 107 is a transparent conductive film.

(substrate)
Examples of the material of the substrate 101 include plastic films and sheets such as glass, quartz, polypropylene, polyethersulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, and polyethylene naphthalate. . In the case of a top emission type organic light emitting electric field element, in addition to this, metal oxides such as silicon oxide and aluminum oxide, metal fluorides such as aluminum fluoride and magnesium fluoride, etc. on the above plastic film and sheet, A light-transmitting substrate made of a single layer or a laminate of metal nitrides such as silicon nitride and aluminum nitride, metal oxynitrides such as silicon oxynitride, and polymer resin films such as acrylic resin, epoxy resin, silicone resin, and polyester resin Alternatively, a metal foil such as aluminum or stainless steel, a sheet, a plate, a light-impermeable base material in which a metal film such as aluminum, copper, nickel, or stainless steel is laminated on a plastic film or sheet can be used. However, the present invention is not limited to these.

The bottom surface of the organic EL display device 100 from which light is extracted may be formed from the electrode side adjacent to the substrate 101 in the bottom emission type. In the top emission type, it may be performed from the electrode side facing the substrate 101.
The substrate 101 made of these materials has a moisture-proofing or hydrophobic property by forming an inorganic film on the entire surface or one surface of the substrate 101, applying a resin, or the like in order to avoid intrusion of moisture or oxygen into the organic EL display device 100. It is preferable to have processed. In particular, in order to avoid the intrusion of moisture into the light emitting medium layer 108, it is preferable to reduce the moisture content and the gas permeability coefficient in the substrate 101.

(Pixel electrode)
The pixel electrode 102 is formed on the substrate 101 and patterned as necessary. The pixel electrode 102 is partitioned by the first partition wall 103A and becomes the pixel electrode 102 corresponding to each pixel.

  As the material of the pixel electrode 102, metal composite oxides such as ITO (indium tin composite oxide), IZO (indium zinc composite oxide), and AZO (zinc aluminum composite oxide), and metal materials such as gold and platinum are used. Can be used. In addition, 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. However, the present invention is not limited to these.

When the pixel electrode 102 is used as an anode, it is preferable to select a material having a high work function such as ITO. In the TFT-driven organic EL display device, the electrode only needs to have a low resistance, and a sheet resistance of 20 Ω · sq or less can be suitably used.
As a method for forming the pixel electrode 102, 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, an ink jet printing method, or a gravure printing is used. An existing film formation method such as a wet film formation method such as a screen printing method or a screen printing method can be used. However, the present invention is not limited to these.

  As a patterning method of the pixel electrode 102, 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 or a film forming method.

In the case of the top emission type, it is preferable to form a reflective layer 207 (see FIG. 2B) below the pixel electrode 102. The material of the reflective layer 207 is preferably high reflectivity and low resistance, single film and laminated film containing one or more of Cr, Mo, Al, Ag, Ta, Cu, Ti, Ni, alloy film, the above A film using a material and a protective film such as SiO, SiO ₂ or TiO ₂ can be used. The reflectance may be 80% or more as a total average in the visible light wavelength region, and if it is 90% or more, it can be suitably used. This is not the case when the light emitting medium layer 108 or the pixel electrode 102 is a light-impermeable material.

As the forming method, depending on the material, dry film forming methods such as resistance heating evaporation method, electron beam evaporation method, reactive evaporation method, ion plating method, sputtering method, ink jet printing method, gravure printing method, screen printing, etc. An existing film formation method such as a wet film formation method such as a method can be used. However, the present invention is not limited to these.
As a patterning method for the reflective layer 207, 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 the material and the film forming method.

(Partition wall)
The partition wall 103 according to the embodiment is formed so as to partition a light emitting region corresponding to each pixel. At this time, the partition wall 103 is preferably formed so as to cover an end portion of the pixel electrode 102. In general, the active drive type organic EL display device 100 is formed so as to cover the end portion of the pixel electrode 102 because the pixel electrode 102 is formed for each pixel and each pixel tries to occupy as large an area as possible. Is done. The most preferable shape of the partition wall 103 in plan view is basically a lattice shape that divides the pixel electrodes 102 by the shortest distance.

  The partition wall 103 functions as a partition member that partitions each of the plurality of pixels. For this reason, when the light emitting medium layer 108 is disposed in each pixel by patterning using a wet coating method, the partition wall 103 can prevent color mixing between adjacent pixels.

  The partition wall 103 of this embodiment is provided with a two-layer structure of a first partition wall portion 103A having a reverse tapered shape in cross section and a second partition wall portion 103B having a forward tapered shape in cross section. As a result, the leakage current in the light emitting medium layer 108 formed on the entire display area as described later is reduced.

  Since the first partition wall portion 103A has an inversely tapered cross section, the wall surface of the first partition wall portion 103A is at an angle of less than 90 degrees with the surface of the substrate 101 as shown in FIG. That is, the interval between the adjacent first partition walls 103 </ b> A is set so as to decrease as the distance from the substrate 101 increases.

  Here, the first partition wall portion 103 </ b> A may rise vertically with respect to the substrate 101 (vertical structure). In this case, the angle between the wall surface of the first partition wall portion 103A and the surface of the substrate 101 is 90 degrees, and the interval between the adjacent first partition wall portions 103A is equal along the direction away from the substrate 101. .

  The width of the bottom of the second partition 103B on the substrate 101 side is set to be equal to the width of the upper portion of the first partition 103A. Accordingly, no step is formed between the first partition wall portion 103A and the second partition wall portion 103B. And since the 2nd partition part 103B is a cross-sectional taper shape, the space | interval between adjacent 2nd partition part 103B is set so that it may become large, so that it leaves | separates from the board | substrate 101. FIG.

  As described above, the partition wall 103 includes at least two layers of the first partition wall portion 103A and the second partition wall portion 103B on the first partition wall portion. The first partition wall portion 103A is, for example, perpendicular to the substrate, or A reverse taper shape is provided. Furthermore, the second partition wall 103B is provided with the same width at the bottom of the second partition wall 103B with respect to the width of the upper part of the first partition wall 103A. As a result, it is possible to prevent disconnection of electrodes formed on the organic light emitting medium layer and leakage current to the partition walls.

  That is, by forming the first partition wall portion 103A so as to rise perpendicularly to the substrate or in an inversely tapered shape, the hole transport layer formed on the electrode can be physically disconnected, Prevent leakage current from the electrode to the barrier rib. As a result, a current flows only in the pixel electrode, and uneven light emission can be suppressed.

  Further, by providing the second partition wall portion with the same width as the top of the first partition wall portion 103A and the bottom of the second partition wall portion 103B, the influence of the sharp edge of the first partition wall portion 103A is suppressed, and the electrode is disconnected. Thus, it is possible to manufacture an EL display device with no display failure and good EL characteristics.

  In particular, by providing the film thickness of the first partition 103A equal to or greater than the total film thickness of the organic light emitting medium layer, the disconnection of the electrode formed on the organic light emitting medium layer and the connection to the partition are more reliably performed. Leakage current can be prevented.

The first partition 103A of the present embodiment is made of an inorganic insulating material.
The inorganic insulating material that forms the first partition 103A can be formed by a dry coating method typified by a sputtering method, a plasma CVD method, or a resistance heating vapor deposition method. In addition, after applying the ink containing the inorganic insulating material using a known coating method such as a spin coater, bar coater, roll coater, die coater, gravure coater, etc., the solvent is removed in a baking process such as air drying or heat drying. The inorganic insulating film may be removed.

  Next, a photosensitive resin is applied on the inorganic insulating film, and exposure and development are performed to form a pattern. As the photosensitive resin, either a positive type resist or a negative type resist is used. A commercially available resist may be used. Examples of the step of forming a pattern include a method of obtaining a predetermined pattern using a photolithography method. In the present invention, the present invention is not limited to the above method, and other methods may be used. If necessary, surface treatment such as plasma irradiation or UV irradiation may be performed on the inorganic insulating film.

  In order to form the reverse tapered structure and the vertical structure constituting the first partition wall 103A, a dry etching method represented by reactive ion beam etching, reactive gas etching, reactive ion etching, or the like can be used. In addition, a wet etching method using a liquid chemical having a property of being dissolved by corrosion can be used.

  A preferable film thickness of the first partition wall 103A is preferably 50 nm or more and 1000 nm or less in order to ensure insulation. Further, in order to suppress disconnection of the counter electrode 107 (cathode) 107, it is preferable that the height is the same as the height of the organic light emitting medium layer 108, and the film thickness of the first partition wall portion 103A is set to the film thickness of the organic light emitting medium layer. On the other hand, it can use suitably by making it equivalent or more.

  The material of the second partition wall portion 103B 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, a photo-curing resin of a photo radical polymerization system, a photo cationic 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. In addition, as a material for forming the partition wall 103, SiO2, TiO2, or the like can be used.

  The preferred height of the second partition wall 103B is not less than 0.1 μm and not more than 30 μm, and more preferably not less than 0.5 μm and not more than 2 μm. If it is higher than 30 μm, the formation and sealing of the counter electrode 107 (cathode) 107 is hindered, and if it is lower than 0.1 μm, the end of the pixel electrode 102 cannot be covered, or a short circuit with an adjacent pixel when the light emitting medium layer 108 is formed This is because they will mix and color.

  As a method for forming the second partition wall 103B, 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, an ink jet printing method, Existing film forming methods such as a wet film forming method such as a gravure printing method and a screen printing method can be used. However, the present invention is not limited to these.

  As a patterning method for the second partition wall 103B, an inorganic film is uniformly formed on the substrate (the substrate 101 and the pixel electrode 102) according to the material and the film forming method, masked with a resist, and then dry-etched. Examples thereof include a method and a method in which a photosensitive resin is applied on a substrate and a predetermined pattern is formed by a photolithography method. The photolithography method can be preferably used because the bottom width of the second partition wall portion 103B can be formed to be equal to the width of the upper portion of the first partition wall portion 103A. The present invention is not limited to these, and other methods may be used as long as the bottom width of the second partition wall portion 103B can be formed to be equal to the width of the upper portion of the first partition wall portion 103A.

  If necessary, add a water repellent to the resist and the photosensitive resin, make a multilayer structure of hydrophilic and hydrophobic materials, or irradiate with plasma or UV to form the next film-forming material. Water repellency or hydrophilicity can also be imparted.

(Hole injection layer, hole transport layer)
Next, the hole injection layer is a layer having a function of injecting holes from the transparent electrode (anode), and the hole transport layer 104 is a layer having a function of transporting holes to the light emitting layer. These layers may have both a hole injection function and a hole transport function. In this case, the functional layer is referred to by either one name or both names depending on the degree of these functions. In the present embodiment, the layer called the hole transport layer 104 also includes a hole injection layer.

The physical property value of the hole transport layer 104 preferably has a work function equal to or higher than that of the pixel electrode 102101. This is because holes are efficiently injected from the pixel electrode 102 to the interlayer 105. Although it varies depending on the material of the pixel electrode 102101, 4.5 eV or more and 6.5 eV or less can be used. When the pixel electrode 102101 is ITO or IZO, 5.0 eV or more and 6.0 eV or less can be suitably used. The specific resistance of the hole transport layer 104 is preferably 1 × 10 ³ to 2 × 10 ⁶ Ω · m, more preferably 5 × 10 ³ to 1 × 10 ⁶ Ω, with a film thickness of 30 nm or more. -M. Further, in the bottom emission structure, emitted light is extracted from the pixel electrode 102 side. If the light transmittance is low, the extraction efficiency decreases. Therefore, the total average in the visible light wavelength region is preferably 75% or more, and if it is 85% or more. It can be preferably used.

As a material constituting the hole transport layer 104, for example, a polymer material such as polyaniline, polythiophene, polyvinyl carbazole, a mixture of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid can be used. In addition, a conductive polymer having a conductivity of 10 ⁻² S / cm or more and 10 ⁻⁶ S / cm or less can be preferably used. The polymer material can be used in a film forming process by a wet method. Therefore, it is preferable to use a polymer material when forming the hole injection layer or the hole transport layer 104. Such a polymer material is dispersed or dissolved in water or a solvent and used as a dispersion or solution.

When an inorganic material is used as the hole transport material, Cu ₂ O, Cr ₂ O ₃ , Mn ₂ O ₃ , FeOx (x to 0.1), NiO, CoO, Bi ₂ O ₃ , SnO ₂ , ThO ₂ Nb ₂ O ₅ , Pr ₂ O ₃ , Ag ₂ O, MoO ₂ , ZnO, TiO ₂ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , MoO ₃ , WO ₃ , MnO _2, etc. Can do.

  As a method of forming the hole transport layer 104, a method of forming the hole transport layer 104 on the entire display region on the substrate 101 by a simple method such as a spin coating method, a die coating method, a dipping method, or a slit coating method is employed. In forming the hole transport layer 104, ink (liquid material) in which the hole transport material is dissolved in water, an organic solvent, or a mixed solvent thereof is used. 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. In addition, surfactants, antioxidants, viscosity modifiers, ultraviolet absorbers and the like may be added to the ink. When the hole transport layer 104 is an inorganic material, it can be formed using a dry process 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.

(Interlayer)
The interlayer 105 has a function of improving the light emission lifetime of the device by being laminated between the organic light emitting layer 106 and the hole transport layer 104. In the top emission type element structure, the hole transport layer 104 can be stacked after being formed. Usually, the hole transport layer 104 is formed so as to cover it, but patterning may be performed as necessary.

Examples of the material of the interlayer 105 include polyvinyl carbazole or derivatives thereof, polyarylene derivatives having an aromatic amine in the side chain or main chain, polymers containing aromatic amines such as arylamine derivatives and triphenyldiamine derivatives, etc. Is mentioned. In the inorganic _{materials, Cu 2 O, Cr 2 O} 3, Mn 2 O 3, NiO, CoO, Pr 2 O 3, Ag 2 O, MoO 2, ZnO, TiO 2, V 2 O 5, Nb 2 O 5, Examples thereof include transition metal oxides such as Ta ₂ O ₅ , MoO ₃ , WO ₃ and MnO ₂ , and inorganic compounds containing one or more of these nitrides and sulfides. However, the present invention is not limited to these.

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

  As these interlayer materials, it is preferable to select a material having a work function equal to or higher than that of the hole transport layer 104, and more preferable to have a work function equal to or lower than that of the organic light emitting layer 106. This is because an unnecessary injection barrier is not formed when carriers are injected from the hole transport layer 104 into the organic light emitting layer 106. Further, in order to obtain an effect of confining charges that could not contribute to light emission from the organic light emitting layer 106, the band gap is preferably 3.0 eV or more, and more preferably 3.5 eV or more.

  As a method for forming the interlayer 105, an existing film formation method such as a wet film formation method such as an ink jet printing method, a relief printing method, a gravure printing method, or a screen printing method can be used depending on the material.

  Here, the relief printing method may use, for example, a relief printing apparatus 300 shown in FIG. In FIG. 3, reference numeral 301 denotes a stage, reference numeral 302 denotes a substrate to be printed, reference numeral 303 denotes an ink tank, reference numeral 304 denotes an ink chamber, reference numeral 305 denotes an anilox roll, reference numeral 306 denotes a doctor, reference numeral 307 denotes a letterpress. , 308 indicates a plate cylinder, and 309 indicates an ink layer.

(Organic light emitting layer 106)
In the case of a top emission type element, the organic light emitting layer 106 can be laminated after the formation of the interlayer 105. When the display light emitted from the organic light emitting layer 106 is monochromatic, it is formed so as to cover the interlayer 105. However, in order to obtain multicolor display light, it is preferably used by performing patterning as necessary. it can.

  Examples of the organic light-emitting material forming the organic light-emitting layer 106 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, polymethyl methacrylate, polyvinylcarbazole, and polyarylene, polyarylene vinylene, and polyfluorene polymers Materials. However, the present invention is not limited to these.

  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 solubility of the organic light emitting material. Moreover, surfactant, antioxidant, a viscosity modifier, a ultraviolet absorber, etc. may be added 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 106, an existing film formation method such as a wet film formation method such as an ink jet printing method, a relief printing method, a gravure printing method, or a screen printing method can be used depending on the material.

(Counter electrode)
Next, the counter electrode 107 is formed on the organic light emitting layer 106.
For the material of the counter electrode 107, for example, 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 108. High Al or Cu may be laminated and used. 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, An alloy system with a metal element such as Al or Cu may be used. Specifically, alloys such as MgAg, AlLi, and CuLi can be used. A transparent conductive film such as a metal composite oxide such as ITO (indium tin composite oxide), IZO (indium zinc composite oxide), or AZO (zinc aluminum composite oxide) can be used.

  Since these counter electrodes 107 in the top emission structure transmit the display light emitted from the light emitting medium layer 108, the counter electrodes 107 need to have a light transmission property in the visible light wavelength region. In the case of simple metals such as Mg, Al, and Yb, the thickness is preferably 20 nm or less, and more preferably in the range of 2 nm to 7 nm. The transparent conductive film can be suitably used by adjusting the film thickness so that the average light transmittance in the visible light wavelength region is maintained at 85% or more.

  As a method of forming the counter electrode 107, 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, an ink jet printing method, or a gravure printing method. However, in the present invention, the present invention is not limited to these.

(Sealed body)
For example, the sealing body 109 is sealed by bonding the sealing body 109 and the substrate 101 to the periphery of the substrate 101 on which the pixel electrode 102, the partition wall 103, the light emitting medium layer 108, and the counter electrode 107 are formed. Is done. At this time, in the top emission structure, display light radiated from the light emitting medium layer 108 through the sealing body 109108 opposite to the substrate 101 side is extracted, so that light transmittance is required for the visible light wavelength region. The light transmittance is preferably 85% or more as the average light transmittance in the visible light wavelength region. In addition, the sealing body 109 is formed with, for example, the pixel electrode 102, the partition wall 103, the light emitting medium layer 108, and the counter electrode 107. Alternatively, the resin layer 111 may be provided over the sealing material 110 over the substrate 101, and the sealing material 110 and the substrate 101 may be bonded to each other with the resin layer 111 (see FIG. 1).

At this time, the material of the sealing material 110 needs to be a base material having low light transmittance of moisture and oxygen. 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 a plastic substrate, films with low light transmission and water-absorbing films, or polymer films coated with a water-absorbing agent. The water vapor light permeability of the film is preferably 10E ⁻⁶ g / m ² / day or less.

  Examples of the resin layer 111 include a photo-curing adhesive resin made of an epoxy resin, an acrylic resin, a silicone resin, a thermosetting adhesive resin, a two-component curable adhesive resin, an ethylene ethyl acrylate (EEA) polymer, and the like. Acrylic resins, 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. Examples of the method for forming the resin layer 111110 on the sealing material 110 include a solvent solution method, an extrusion lamination method, a melting / hot melt method, a calendar method, a nozzle coating method, a screen printing method, a vacuum laminating method, and a hot roll laminating. Law. A material having a hygroscopic property or an oxygen absorbing property may be contained as necessary. The thickness of the resin layer 111 formed on the sealing material 110 is arbitrarily determined depending on the size and shape of the organic EL element to be sealed, but is preferably about 5 μm to 500 μm.

  The substrate 101 on which the pixel electrode 102, the partition wall 103, the light emitting medium layer 108, and the counter electrode 107 are formed is bonded to the sealing body 109 in a sealing chamber. In the case where the sealing body 109 has a two-layer structure of the sealing material 110 and the resin layer 111 and a thermoplastic resin is used for the resin layer 111, 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. Note that although the resin layer 111 is formed over the sealing material 110 here, the resin layer 111 may be formed over the substrate 101 and bonded to the sealing material 110.

  An inorganic thin film such as a silicon nitride film is formed using a dry process such as an EB vapor deposition method or a CVD method, for example, as a passivation film instead of the sealing material 110209 or in place of the sealing material 110. Thus, the sealing body 109 can be used, or these can be combined. The thickness of the passivation film may be in the range of 100 nm to 500 nm and varies depending on the moisture permeability of the material, water vapor light permeability, and the like, but a thickness of 150 nm to 300 nm can be preferably used. In the top emission type structure, it is necessary to consider light transmittance in addition to the above characteristics, and it can be suitably used as long as it is 70% or more in the total average in the visible light wavelength region.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  Next, examples of the organic EL display device will be described based on the above-described embodiment. In addition, this invention is not restrict | limited by the following Example.

[Example]
First, a 5 inch diagonal glass substrate was prepared. On this glass substrate, an ITO (indium-tin oxide) thin film having a thickness of 50 nm was formed by sputtering, and patterning was performed by photolithography. Thus, the pixel electrode 102 having a plurality of line patterns was produced. In the plurality of line patterns, 320 lines with a pitch of 30 μm and a width of 136 μm are formed. Next, this substrate 101 was cleaned by a conventional wet process such as acetone, pure water, brush cleaning, ultrasonic cleaning, etc., and then cleaned by U V ozone treatment.

Next, the first partition wall 103A was formed as follows. SiN was deposited using the CVD method so that the entire display area was deposited. In the CVD method, SiH ₄ , NH ₃ , H ₂ gas having a purity of 99.9999 was used. In the chamber, the substrate 101 was heated by a hot plate, adjusted so that the surface of the substrate 101 was 130 ° C., and formed into a film with a plasma power of 1.5 kW for 200 seconds to obtain a film thickness of 600 nm. At this time, SiH ₄ , NH ₃ , and H ₂ were supplied at a ratio of 1: 2: 10 so that the degree of vacuum was 150 Pa. Since the formed SiN film was uneven due to the step between the ITO and the surface of the substrate 101, the surface was polished and planarized from the surface of the substrate 101 to 200 nm.

  Next, a body type photosensitive resist (manufactured by Nippon Zeon Co., Ltd., ZEP520A) was spin coated on the first partition wall 103A. As spin coating conditions, the film was rotated at 4000 rpm for 50 seconds, and then baked on a hot plate at 180 ° C. for 5 minutes to form a thin film. After the resist film was formed, the resist pattern was formed by performing exposure, development, and washing, leaving only the portion to be the first partition wall 103A.

  After the resist pattern is formed, the reverse tapered shape of the first partition wall 103A is formed by reactive ion etching. As the reactive gas, fluorine and oxygen were used, and a mixed gas of fluorine gas and oxygen gas was introduced into the chamber. Each flow rate was adjusted, the flow rate of fluorine gas was 100 sccm, the flow rate of oxygen gas was 400 sccm, and the pressure in the chamber was adjusted to 10 Pa. Moreover, high frequency power 700W of 13.56 MHz was applied from the high frequency power supply. The silicon nitride film other than the partition wall 103 was removed by dry etching, and the taper angle from the substrate 101 was 150 degrees, and the first partition wall 103A having a reverse taper shape with an upper portion of 30 μm and a bottom portion of 27 μm was formed. After dry etching, the resist was peeled off.

Next, the second partition 103B was formed as follows. A positive photosensitive polyimide (Photo Nice, DL-1000 manufactured by Toray Industries Inc.) was spin coated on the entire surface of the substrate 101 so as to cover the first partition wall 103A. As conditions for spin coating, the glass substrate was rotated at 110 rpm for 5 seconds, and then the glass substrate was rotated at 400 rpm for 20 seconds. The film thickness of the positive photosensitive polyimide is 1.5 μm. A photomask hidden only on the first partition wall portion 103A is prepared, and a portion other than the first partition wall portion 103A portion of the photosensitive material applied to the entire surface of the substrate 101 by using a photolithography method is 180 mJ / cm ² using an i-line stepper. Exposed. After the exposure, development was performed, and baking was performed at 230 ° C. for 30 minutes using an oven to obtain a second partition wall portion 103B on the first partition wall portion 103A. The second partition wall portion 103B thus formed had a taper angle of 50 degrees from the top of the first partition wall portion 103A, the bottom was 30 μm and the top was 15 μm, which was the same width as the top of the first partition wall 103A. Next, ultraviolet irradiation was performed as a surface treatment of ITO.

Next, the hole transport layer 104 was formed. Molybdenum oxide was used as an inorganic material constituting the hole transport layer 104. An inorganic material was deposited to a thickness of 50 nm using a sputtering method so that the entire surface of the display region was deposited. In the sputtering method, a molybdenum metal target having a purity of 99.9% was used, and a molybdenum oxide film was formed on the substrate 101 by a DC magnetron sputtering method. The power density of the target is 1.3 W / cm ² . The ratio of the mixed gas supplied into the chamber is 2 for argon and 1 for oxygen. The exhaust valve provided in the chamber was adjusted so that the degree of vacuum during sputtering was 0.5 Pa, and the amount of gas supplied to the chamber was adjusted. The film thickness of molybdenum oxide was controlled by adjusting the sputtering time. In the patterning process, a metal mask having an opening of 120 mm × 300 mm was used.

  At this time, the molybdenum oxide film formed on the partition wall 103 was divided by the inverse tapered shape of the first partition wall portion 103A.

  Next, an ink in which a polyvinyl carbazole derivative, which is a material of the interlayer 105, is dissolved in toluene so as to have a concentration of 0.5% is used, and the interlayer 105 is directly above the hole transport layer 104 sandwiched between the partition walls 103. Was printed by a relief printing method so as to match the line pattern of the pixel electrode 102. The film thickness of the interlayer 105 after printing and drying was 20 nm.

Next, a polyphenylene vinylene derivative was employed as the organic light emitting material, and an organic light emitting ink in which this material was dissolved in toluene was prepared so that the concentration of this material was 1%. Using this ink, the light emitting layer 106 was printed on the pixel electrode 102 sandwiched between the partition walls 103 by using a relief printing method so as to match the line pattern of the pixel electrode 102. The film thickness of the light emitting layer dried after the printing step is 80 nm, and the film is formed so that the total film thickness of the hole transport layer 104, the interlayer 105, and the light emitting layer is equal to the height of the first partition wall portion 103A. did.
Next, a calcium film and a cathode layer (counter electrode 107) made of an aluminum film were formed on the light emitting layer in a line pattern using a metal mask. Specifically, the resistance heating vapor deposition method was used so that the line pattern of the cathode layer and the line pattern of the pixel electrode 102 were orthogonal, and the film thickness was 100 nm.

  Thereafter, sealing was performed using a glass in which a thick glass central portion was processed into a concave shape so as to cover the upper portion of the cathode as the sealing body 109. A hygroscopic agent was installed in the concave portion of the glass to reduce deterioration due to the sealing environment.

  In the peripheral portion of the display portion of the organic EL display panel obtained in this way, an anode-side extraction electrode connected to each pixel electrode 102 and a cathode-side extraction electrode connected to the cathode layer are provided. It has been. These extraction electrodes were connected to a power source, the organic EL display element was turned on and displayed, and the lighting state and the display state were confirmed.

When the obtained organic EL display element was driven and display was confirmed, a luminance of 600 cd / cm ² was obtained at a driving voltage of 7 V, no crosstalk due to leakage current was observed, and the light emission state was good. It was.

[Comparative Example 1]
First, the pixel electrode 102 was formed by the same method as in the above embodiment.
Next, positive type photosensitive polyimide (Photo Nice, DL-1000 manufactured by Toray Industries, Inc.) was spin coated on the front surface of the substrate without forming the first partition wall. As conditions for spin coating, the glass substrate was rotated at 300 rpm for 20 seconds after the glass substrate was rotated at 110 rpm for 5 seconds. The film thickness of the positive photosensitive polyimide is 1.8 μm. Exposure, development, and baking were performed by the same method as in the embodiment to form the second partition wall 103B. The partition wall formed in this manner had a taper angle of 45 degrees with the substrate, the top of the head was 15 μm, and the bottom was 35 μm.

Next, as in the above embodiment, an ITO surface treatment, a hole transport layer, a light emitting layer, and a cathode layer were formed. When the organic EL display device thus obtained was driven, a luminance of 250 cd / cm ² was obtained with a driving voltage of 7 V, and crosstalk due to leakage current occurred.

  From the evaluation result of the comparative example 1, since the reverse taper shape of the 1st partition part was not contained in the partition, the leakage current generate | occur | produced and the crosstalk or the fall of the light emission luminance occurred. In the above embodiment, since the hole transport layer is divided by the inverse tapered shape of the first partition wall portion, the leakage current is reduced or suppressed, crosstalk is not generated, and an organic EL display element with high emission luminance is obtained. Obtained.

[Comparative Example 2]
Produced by the same method as in the above embodiment, except that the step is 400 nm from the substrate surface in the stage of polishing the surface of the first partition wall, and the second partition wall 103B is set to the width of the upper part of the first partition wall. The bottom of the second partition wall portion was narrowed by about 5 nm, and the total film thickness of the hole transport layer, the interlayer, and the light emitting layer was 200 nm lower than the height of the first partition wall portion.

  Next, as in the above example, an ITO surface treatment, a hole transport layer, a light emitting layer, and a cathode layer were formed. When the organic EL display device thus obtained was driven, non-light emitting pixels were confirmed in several places.

  From the evaluation result of Comparative Example 2, the cathode was disconnected due to the sharp edge of the first partition wall, resulting in a display failure. In the above embodiment, the second partition wall portion has the same width as the top of the first partition wall portion, and the bottom of the second partition wall portion has the same width, and the thickness of the first partition wall portion is the total thickness of the organic light emitting medium layer. By providing the film thickness equal to or greater than the film thickness, it is possible to suppress the influence of the sharp edges of the first partition wall, prevent disconnection of the electrodes, and obtain an EL display device having no display failure and good EL characteristics. It was.

[Comparative Example 3]
It was produced by the same method as in Comparative Example 2 except that the thickness of the cathode layer was 100 to 300 nm in order to prevent disconnection. When the organic EL display element thus obtained was driven, a luminance of 150 cd / cm ² was obtained at a driving voltage of 7 V, and there was no non-light emitting pixel, but it was about 100 cd / cm ² lower than that of the example. Brightness was obtained.

  From the evaluation results of Comparative Example 3, it was necessary to laminate the cathode thickly in order to prevent disconnection, and the luminance was lowered due to characteristic deterioration due to thermal history damage during resistance heating vapor deposition. In the above embodiment, the second partition wall portion has the same width as the top of the first partition wall portion, and the bottom of the second partition wall portion has the same width, and the thickness of the first partition wall portion is the total thickness of the organic light emitting medium layer. Since the influence of the sharp edge of the first partition wall portion can be suppressed by providing the film thickness equal to or greater than the film thickness, it is not necessary to laminate the cathode thickly, and an EL display device with favorable EL characteristics can be obtained.

  INDUSTRIAL APPLICABILITY The present invention is useful for an organic EL display device that can reduce or suppress leakage current and that has good EL characteristics, and a method for manufacturing the same. In addition, the present invention is useful for an organic EL element, an image display apparatus, and an image display apparatus manufacturing method in which leakage current is reduced and element characteristics are improved.

DESCRIPTION OF SYMBOLS 100 Organic EL display device 101 Substrate 102 Pixel electrode 103 Partition 103A First partition part 103B Second partition part 104 Hole transport layer 105 Inter layer 106 Organic light emitting layer 107 Counter electrode 108 Organic light emitting medium layer 109 Sealing body 110 Sealing material 111 Resin layer 207 Reflective layer

Claims (10)

An organic EL element formed by placing a pixel electrode and a counter electrode facing each other on a substrate with an organic light emitting medium layer including a hole transport layer and an organic light emitting layer interposed therebetween,
On the substrate, partition walls having an insulating property are formed to partition the pixel electrode, and the partition wall includes at least a first partition wall portion and a second partition wall portion formed on the partition wall from the side closer to the substrate. Has two layers,
The wall surface of the first partition wall has an angle of 90 degrees or less than 90 degrees with the substrate surface,
An organic EL element, wherein a width of a bottom portion on the substrate side of the second partition wall portion is the same as or substantially the same as a width of an upper portion of the first partition wall portion.   The organic EL element according to claim 1, wherein the first partition wall portion is an inorganic insulating material.   3. The organic EL according to claim 1, wherein a thickness of the first partition wall portion is equal to or greater than a total thickness of the organic light emitting medium layer. element. The pixel electrode is a transparent electrode;
The organic EL element according to claim 1, wherein the hole transport layer is disposed closer to the pixel electrode than the organic light emitting layer. The counter electrode is a transparent electrode;
The organic EL element according to claim 1, wherein the hole transport layer is disposed closer to the pixel electrode than the organic light emitting layer. A method for producing an organic EL device, wherein a pixel electrode and a counter electrode are arranged opposite to each other on a substrate with an organic light emitting medium layer including a hole transport layer and an organic light emitting layer interposed therebetween,
In preparation for a partition forming step of forming a partition for partitioning the pixel electrode on the substrate,
The partition wall forming step includes a first step of forming a first partition wall portion and a second step of forming a second partition wall portion on the first partition wall portion,
The wall surface of the first partition wall is formed so that the angle formed with the substrate surface is 90 degrees or less than 90 degrees,
A method of manufacturing an organic EL element, wherein the width of the bottom portion on the substrate side of the second partition wall portion is formed to be the same as or substantially the same as the width of the upper portion of the first partition wall portion.   The method of manufacturing an organic EL element according to claim 6, wherein the first partition wall portion is made of an inorganic insulating material.   The film thickness of the said 1st partition part is formed so that it may become equal to the total film thickness of an organic light emitting medium layer, or it may become thicker than the total film thickness of the said organic light emitting medium layer. The manufacturing method of the organic EL element described in 2. The pixel electrode is a transparent electrode;
The organic EL device according to any one of claims 6 to 8, wherein the hole transport layer is disposed closer to the pixel electrode than the organic light emitting layer. The counter electrode is a transparent electrode;
The organic EL device according to any one of claims 6 to 8, wherein the hole transport layer is disposed closer to the pixel electrode than the organic light emitting layer.

Images