JP2018116830A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL element which can sufficiently reduce the unevenness in light emission attributed to the unevenness in coating when forming a layer which constitutes organic EL layers, by coating, and the unevenness in light emission caused by addition of a flaw to a layer, such as a light-emitting layer, which constitutes organic EL layers, due to a crack in a manufacturing process.SOLUTION: There is provided an organic EL element 10, comprising: a transparent substrate 4; a transparent first electrode layer 2 on one face of the transparent substrate 4; an organic EL layer 3 on a face of the first electrode layer 2 on a side opposite to the transparent substrate 4, which includes a light-emitting layer; a second electrode layer 4 on a face of the organic EL layer 3 on a side opposite to the first electrode layer 2; a transparent layer 5 on a face of the transparent substrate 4 on a side opposite to the first electrode layer 2; and a diffusion layer 6 on a face of the transparent layer 5 on a side opposite to the transparent substrate 4.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present disclosure relate to an organic electroluminescent device including a diffusion layer.

  The organic electroluminescence element has high visibility due to self-coloring, is an all-solid-state display unlike a liquid crystal display device, has excellent impact resistance, has a fast response speed, is less affected by temperature changes, and Advantages such as a wide viewing angle are attracting attention. Hereinafter, organic electroluminescence may be abbreviated as organic EL.

  The organic EL element usually has a configuration in which a transparent substrate, a transparent first electrode layer, an organic EL layer including a light emitting layer, and a second electrode layer are sequentially laminated. In the organic EL element, light is extracted from the light emitting layer through the first electrode layer and the transparent substrate. At this time, if unevenness or a defect occurs in the organic EL layer, it becomes uneven light emission. There is a problem that the quality deteriorates.

  Thus, for example, Patent Documents 1 and 2 disclose a technique of providing a diffusion layer that diffuses light between the transparent substrate and the first electrode layer to reduce light emission unevenness. For example, Patent Document 3 discloses a technique in which a diffusion layer is provided on the surface of the transparent substrate opposite to the first electrode layer to reduce unevenness in light emission.

JP 2012-69920 A JP 2012-178268 A JP 2014-229546 A

  By the way, when the diffusion layer is provided in the organic EL element as in Patent Documents 1 to 3, slight light emission unevenness can be reduced, but it is difficult to reduce even large light emission unevenness. Specifically, light emission unevenness caused by coating unevenness when a layer constituting an organic EL layer such as a light emitting layer is formed by a coating method, or scratches on a layer constituting the organic EL layer such as a light emitting layer in the manufacturing process. It is difficult to reduce light emission unevenness caused by entering even if a conventional technique of providing a diffusion layer is used.

  The present disclosure has been made in view of the above problems, and a main object thereof is to provide an organic EL element capable of sufficiently reducing unevenness in light emission.

  One embodiment of the present disclosure includes a transparent substrate, a transparent first electrode layer on one surface of the transparent substrate, and a light emitting layer, and the first electrode layer is opposite to the transparent substrate. An organic electroluminescence layer on the surface, a second electrode layer on the surface of the organic electroluminescence layer opposite to the first electrode layer, and a side of the transparent substrate opposite to the first electrode layer. Provided is an organic electroluminescence device having a transparent layer on a surface and a diffusion layer on the surface of the transparent layer opposite to the transparent substrate.

  In one embodiment of the present disclosure, there is an effect that the organic EL element can be an organic EL element capable of sufficiently reducing light emission unevenness.

It is a schematic sectional drawing which shows an example of the organic EL element of this indication. It is a schematic perspective view for demonstrating the transparent layer in this indication. It is a schematic sectional drawing which shows the other example of the organic EL element of this indication. 2 is a photograph showing the results of Example 1 and Comparative Example 1. FIG. It is a schematic sectional drawing which shows an example of the conventional organic EL element.

  In this specification, when a certain configuration such as a certain member or a certain region is “above (or below)” another configuration such as another member or another region, unless otherwise limited, This includes not only when directly above (or directly below) another configuration, but also when above (or below) another configuration, i.e., another configuration above (or below) another configuration. This includes cases where elements are included.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the present disclosure can be implemented in many different modes, and should not be construed as being limited to the description of the embodiments described below. Further, in order to clarify the description, the drawings may be schematically represented with respect to the width, thickness, shape, etc. of each part as compared with the embodiment, but are merely examples, and the interpretation of the present disclosure may be interpreted. It is not limited. In addition, in the present specification and each drawing, elements similar to those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description may be omitted as appropriate. Further, for convenience of explanation, the description may be made using the terms “upper” or “lower”, but the vertical direction may be reversed.

  Hereinafter, the organic EL element in one embodiment of the present disclosure will be described.

  The organic EL device of the present disclosure includes a transparent substrate, a transparent first electrode layer on one surface of the transparent substrate, and a light emitting layer, and the first electrode layer is opposite to the transparent substrate. An organic EL layer on the surface, a second electrode layer on the surface of the organic EL layer opposite to the first electrode layer, and a surface of the transparent substrate on the side opposite to the first electrode layer A transparent layer and a diffusion layer on the surface of the transparent layer opposite to the transparent substrate.

The organic EL element of the present disclosure will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view illustrating an example of the organic EL element of the present disclosure. As illustrated in FIG. 1, the organic EL element 10 of the present disclosure includes a transparent substrate 1, a transparent first electrode layer 2 on one surface of the transparent substrate 1, and a light emitting layer. The organic EL layer 3 on the surface of the layer 2 opposite to the transparent substrate 1, the second electrode layer 4 on the surface of the organic EL layer 3 opposite to the first electrode layer 2, and the transparent substrate 1 The transparent layer 5 on the surface opposite to the first electrode layer 2 and the diffusion layer 6 on the surface opposite to the transparent substrate 1 of the transparent layer 5 are included.

  As shown in FIG. 5, the conventional organic EL element 10 ′ is emitted from the transparent substrate 1 side by providing a diffusion layer 6 on the surface of the transparent substrate 1 opposite to the first electrode layer 2. Diffuses light. The inventor of the present disclosure has studied the conventional organic EL element 10 ′ having such a configuration. Although slight light emission unevenness has been reduced, for example, a layer constituting an organic EL layer such as a light emitting layer is applied by a coating method. Discovered the problem that relatively large light emission unevenness such as light emission unevenness caused by coating unevenness when it was created by, or light emission unevenness caused by scratches on the light emitting layer in the manufacturing process cannot be sufficiently reduced did. Then, when this inventor of this indication repeated further examination, as shown to the organic EL element 10 of this indication shown in FIG. 1, between the transparent base material 1 and the diffusion layer 6, the transparent layer 5 is provided. It has been found that the above-described problems can be solved by providing them. About this reason, the following is estimated.

  That is, when light is irradiated from the surface emitting source, the light beam travels while spreading radially. Therefore, the area illuminated with light tends to increase in proportion to the distance from the surface light source. Then, when the transparent layer is provided between the transparent base material and the diffusion layer as in the organic EL element of the present disclosure, the thickness of the transparent layer is larger than that of the conventional organic EL element in which the transparent layer is not provided. Since the distance from the surface light source becomes longer by an amount corresponding to, light can be illuminated over a wider area with the same luminous flux. In other words, when a transparent layer is provided as in the organic EL element of the present disclosure, the luminous flux illuminated by each area is reduced as compared with a conventional organic EL element in which no transparent layer is provided. Therefore, when a transparent layer is provided as in the organic EL element of the present disclosure, light emission unevenness itself can be reduced, and the light flux passes through the diffusion layer in a state where the light emission unevenness itself is reduced. It is estimated that even a large light emission unevenness can be sufficiently reduced.

  Hereinafter, each configuration in the organic EL element of the present disclosure will be described.

1. Transparent layer The transparent layer in this indication is a member arrange | positioned on the surface on the opposite side to the 1st electrode layer of a transparent base material.

  The transparent layer in this indication should just be arrange | positioned on the surface on the opposite side to the 1st electrode layer 2 of the transparent base material 1, as shown in FIG. Therefore, for example, as shown in FIG. 3, two or more transparent layers 6 may be disposed on the surface of the transparent substrate 1 opposite to the first electrode layer 2. When two or more transparent layers are arranged, it is sufficient that a diffusion layer is arranged on the surface of at least one transparent layer opposite to the transparent base material. Therefore, it is preferable that the diffusion layer is disposed on the surface opposite to the transparent layer on the most transparent substrate side. Moreover, the diffusion layer may be arrange | positioned in the surface on the opposite side to the transparent base material of each transparent layer.

  Since the transparent layer in the present disclosure is a member that is disposed on the light emission surface side of the organic EL element, the transparent layer is a transparent member having predetermined transparency. Here, “having predetermined transparency” means having transparency to the extent that the operator of the organic EL element of the present disclosure does not hinder the visual recognition from the operation surface unless otherwise specified. Therefore, “having predetermined transparency” includes colorless and transparent, and colored transparency that does not hinder visibility, and determines the degree of light transmission according to the application of the organic EL element of the present disclosure. Can do.

  The specific transparency of the transparent layer in the present disclosure is, for example, preferably 50% or more in terms of visible light transmittance, more preferably 60% or more, and particularly preferably 70% or more. . The visible light transmittance can be measured within a measurement wavelength range of 380 nm or more and 780 nm or less using, for example, an ultraviolet-visible near-infrared spectrophotometer (JASCO Corporation: Model V-770DS).

  In the present disclosure, the transparent layer has a refractive index that the diffusion layer has, and a transparent base material that is an upper layer and a lower layer of the transparent layer in order to prevent light emitted from the organic EL layer from being totally reflected by the transparent layer. It is preferable that the refractive index is close. For example, the refractive index difference between the transparent substrate and the diffusion layer and the transparent layer is preferably within a range of ± 30%, more preferably within a range of ± 25%, and particularly within a range of ± 20%. It is preferable that In addition, the above-mentioned “refractive index difference between the transparent base material and the diffusion layer and the transparent layer” means a refractive index difference between the transparent base material and the transparent layer and a refractive index difference between the diffusion layer and the transparent layer.

  The transparent layer in the present disclosure may be, for example, a layer having the above-described transparency, but among them, a layer having a refractive index close to that of the transparent substrate and the diffusion layer is preferable. In the present disclosure, for example, as shown in FIG. 2A, the transparent layer 5 is made of glass such as quartz, alkali glass, alkali-free glass or the like, thin glass, polyethylene, polypropylene, polyethylene terephthalate, polymethacrylate, polymethacrylate. It may be a resin such as methyl methacrylate, polymethyl acrylate, polyester, polycarbonate, polyether sulfone, polyether ether ketone, polyvinyl fluoride, polyolefin, fluorine resin, or transparent as shown in FIG. The layer 5 may be the air layer 51. When the transparent layer 5 is the air layer 51, the transparent layer 5 preferably has a support member 52. Reference numerals not described in FIG. 2 can be the same as those in FIG.

  In the present disclosure, when the transparent layer is an air layer, a frame-like support member 52 may be provided on the outer peripheral portion of the air layer 51 as shown in FIG. A support member may be provided in a pattern on the layer. The pattern shape of the support member at this time can be appropriately selected according to the use of the organic EL element and is not particularly limited, but is preferably a shape that does not reduce the light extraction efficiency of the organic EL element. . Further, the support member may have a mesh shape. When the support member is mesh-shaped, the support member may be provided so as to cover the entire surface of the air layer as long as the transparent layer can maintain predetermined transparency.

  The thickness of the transparent layer in the present disclosure may be a thickness that can provide a predetermined distance between the transparent base material and the diffusion layer, and can exhibit the effect of the present disclosure to sufficiently reduce light emission unevenness. preferable. Specifically, the thickness of the transparent layer is preferably 0.01 mm or more, more preferably 0.05 mm or more, and particularly preferably 0.1 mm or more. In addition, the thickness of the transparent layer in the present disclosure is preferably 6 mm or less, more preferably 3 mm or less, and particularly preferably 1.5 mm or less. Note that the thickness of the transparent layer here corresponds to the thickness of the support member 52 when the transparent layer 5 is composed of the air layer 51 and the support member 52 as shown in FIG.

  The transparent layer in this indication may have a heat dissipation member as needed. Specifically, when the transparent layer in the present disclosure is the air layer 51 as shown in FIG. 2B, a heat dissipation member can be used as the support member 52. Hereinafter, the heat dissipation member will be described.

(Heat dissipation member)
In the present disclosure, by having the heat radiating member, heat accumulated in the organic EL element due to heat generation during driving of the organic EL element can be dissipated to the outside of the organic EL element. Therefore, each member which comprises an organic EL element can suppress malfunctions, such as deterioration by the heat | fever inside an organic EL element, and the luminous efficiency of an organic EL element falling.

  The heat dissipation member in the present disclosure is a member including a metal material. Among these, a member having a desired heat dissipation property is preferable. Examples of the metal material included in the heat dissipation member include aluminum, copper, copper alloy, phosphor bronze, stainless steel (SUS), gold, gold alloy, nickel, nickel alloy, silver, silver alloy, tin, tin alloy, titanium, Iron, iron alloy, zinc, molybdenum, etc. are mentioned. Especially, it is preferable to use aluminum and copper for the heat radiating member in this indication, and it is preferable to use aluminum especially. This is because the metal material described above has excellent heat dissipation and is relatively inexpensive. Moreover, you may use a metal paste as a metal material mentioned above.

  The heat dissipation member in the present disclosure may have an uneven shape on the surface. A heat radiating member having a concavo-convex shape on the surface has a larger surface area than a heat radiating member having a flat surface. Therefore, in the case of a heat radiating member having an uneven shape on the surface, the contact area between the heat radiating member surface and air is increased, and more heat can be diffused to exhibit excellent heat dissipation.

  The uneven shape formed on the heat radiating member is preferably a shape that can increase the surface area of the heat radiating member and increase the contact area with air. Examples of the shape of the convex portion in the concavo-convex shape include a cone shape and a cone shape.

  As for the heat radiating member in this indication, it is preferred that the field by the side of a transparent substrate has light reflectivity. Since the light emitted from the organic EL layer and hitting the heat dissipation member can be reflected again into the organic EL element, the light blocked by the heat dissipation member can be reduced and the light extraction efficiency can be improved. it can. Examples of a method for imparting light reflectivity to the surface of the heat radiating member on the transparent substrate side include, for example, a method of using a light reflective material as the material of the heat radiating member, Examples include a method of forming a light reflection layer. About the material which has light reflectivity, since generally well-known material, for example, a metal material, etc. are mentioned, description here is abbreviate | omitted.

  Examples of a method for forming a heat dissipation member in the present disclosure include a method for forming a metal vapor deposition film using a general vapor deposition method, a method for forming a metal plating film using a general plating method, and adhesion of an epoxy resin or the like. Examples include a method of bonding metal foil through an agent.

(Other)
In the present disclosure, an adhesive, an adhesive, or the like may be used to dispose the transparent layer or the heat dissipation member on the surface of the transparent substrate opposite to the first electrode layer. A previously prepared transparent layer or heat dissipation member can be bonded to the surface of the transparent substrate opposite to the first electrode layer.

  As an adhesive, the material used for a general organic EL element can be employ | adopted, for example, ultraviolet curable resin is mentioned. Specific examples of the pressure-sensitive adhesive include polycarbonate resins, polyolefin resins, acrylic resins, urethane resins, silicone resins, polyester resins, and epoxy resins.

2. Diffusion layer The diffusion layer in this indication is a member arranged on the surface on the opposite side to the transparent substrate of a transparent layer.

  In the present disclosure, as shown in FIG. 1, the diffusion layer 6 may be disposed on at least the surface of the transparent layer 5 opposite to the transparent substrate 1. Therefore, for example, as shown in FIG. 3, the diffusion layer 6 is disposed on the surface of the transparent layer 5 on the side of the transparent substrate 1 in addition to the surface of the transparent layer 5 opposite to the transparent substrate 1. May be. In addition, in this indication, when two or more transparent layers are arranged on the surface opposite to the first electrode layer of the transparent substrate, what is the transparent substrate of at least one of the transparent layers? It is sufficient if a diffusion layer is disposed on the opposite surface, but from the viewpoint of light diffusibility, the diffusion layer is disposed on the opposite surface of the transparent substrate on the most transparent substrate side. It is preferable that Moreover, in this indication, it is preferable that the diffusion layer is arrange | positioned on the surface on the opposite side to the transparent base material of each transparent layer.

  The diffusion layer in the present disclosure is preferably a member capable of improving the light extraction efficiency of the organic EL element, and for example, preferably has a predetermined haze value. Specifically, the haze value of the diffusion layer is preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more. The haze value of the diffusion layer can be 99% or less. In addition, the haze value of the diffusion layer described above is the total haze value that is the sum of the internal haze value and the external haze value of the diffusion layer, and is JIS K using Murakami Color Research Laboratory product number; HM-150. It can be measured by a method based on -7136.

  The diffusion layer in the present disclosure may be a member having a function of diffusing light, and among them, a member having a predetermined haze value as described above is preferable. For example, a member in which light diffusion particles are dispersed in a binder component, a paper containing fibers (for example, Japanese paper), a member having an uneven shape on the surface of the diffusion layer, a member having a pyramid shape, a diffusive film having a diffusion function And a diffusive sheet. As the diffusion layer, for example, when using paper containing fibers such as Japanese paper, a diffusive film or a diffusive sheet having a diffusion function, the diffusion layer can be directly attached to the transparent layer. In the present disclosure, a member in which light diffusion particles are dispersed in a binder component is particularly preferable. In addition, the diffusion layer in the present disclosure may have design properties such as color shading as necessary. When paper containing fibers such as Japanese paper is used as the diffusion layer, the diffusion layer may be a colored transparent member exhibiting a predetermined color, or an arbitrary pattern may be drawn on the diffusion layer. .

  In addition, the paper here refers to the one that is formed thinly and flatly entangled with plant fibers, etc. In the Japanese Industrial Standards (JIS), it is “manufactured by agglomerating plant fibers and other fibers”. Is defined. Therefore, the paper in the present disclosure includes, in addition to Japanese paper, paper defined by the above JIS, that is, paper formed using fibers of various raw materials such as plant-derived raw materials and synthetic resins.

  When the diffusion layer in the present disclosure contains a binder component and light diffusing particles, it is preferable that there is a predetermined refractive index difference between the binder component and the light diffusing particles. For example, the refractive index difference is preferably in the range of 0.01 to 1 and particularly preferably in the range of 0.1 to 0.5. When the difference in refractive index between the binder component and the light diffusing particles is within the above range, excellent light diffusibility can be obtained, and the effect that light emission unevenness can be reduced can be made more remarkable. . The refractive index of the binder component and the light diffusing particles can be measured by, for example, the Becke method, the minimum deflection method, the deflection analysis, the mode line method, the ellipsometry method, and the like.

  The average particle diameter of the light diffusion particles used in the diffusion layer is preferably in the range of 1 μm to 30 μm, for example, and more preferably in the range of 1 μm to 20 μm. When the average particle diameter of the light diffusing particles is within the above range, excellent light diffusibility can be exhibited. The average particle diameter of the light diffusion particles is a value obtained by averaging the diameters of 20 light diffusion particles measured by cross-sectional TEM or STEM observation of the diffusion layer.

  An organic material or an inorganic material can be used for the light diffusion particles used in the diffusion layer. Examples of the organic material used for the light diffusion particles include polyester, polystyrene, melamine resin, (meth) acrylic resin, acrylic-styrene copolymer resin, silicone resin, benzoguanamine resin, benzoguanamine / formaldehyde condensation resin, polycarbonate, polyethylene, Examples include polyolefin. Examples of the inorganic material used for the light diffusing particles include inorganic oxides such as silica, alumina, titania, tin oxide, antimony-doped tin oxide, and zinc oxide fine particles.

  Examples of the binder component used in the diffusion layer include a polymerized photopolymerizable compound (crosslinked product), a solvent-drying resin, a thermosetting resin, and the like. One or more of these resins may be used. it can.

  Examples of the photopolymerizable compound used as the binder component include a photopolymerizable monomer, a photopolymerizable oligomer, or a photopolymerizable polymer. The photopolymerizable monomer is preferably a polyfunctional monomer having two or more photopolymerizable functional groups (that is, bifunctional), such as pentaerythritol triacrylate (PETA) and dipentaerythritol hexaacrylate (DPHA). , Pentaerythritol tetraacrylate (PETTA), dipentaerythritol pentaacrylate (DPPA) and the like. The photopolymerizable oligomer has a weight average molecular weight of more than 1000 and 10,000 or less. Examples of the photopolymerizable oligomer include polyester (meth) acrylate, urethane (meth) acrylate, polyester-urethane (meth) acrylate, polyether (meth) acrylate, polyol (meth) acrylate, melamine (meth) acrylate, and isocyanurate. (Meth) acrylate, epoxy (meth) acrylate, etc. are mentioned. Further, the photopolymerizable polymer has a weight average molecular weight exceeding 10,000. Examples of the photopolymerizable polymer include urethane (meth) acrylate, isocyanurate (meth) acrylate, polyester-urethane (meth) acrylate, epoxy (meth) acrylate, and the like.

  The solvent-drying resin used as the binder component is a resin that forms a film only by drying the solvent added to adjust the solid content during coating, such as a thermoplastic resin. As the solvent dry resin, for example, a general thermoplastic resin can be used. Examples of thermoplastic resins include styrene resins, (meth) acrylic resins, vinyl acetate resins, vinyl ether resins, halogen-containing resins, alicyclic olefin resins, polycarbonate resins, polyester resins, polyamide resins. , Cellulose derivatives, silicone resins and rubbers or elastomers.

  Further, examples of the thermosetting resin used as the binder component include phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine-urea. Examples thereof include a co-condensation resin, a silicon resin, and a polysiloxane resin.

  In addition to the above-described materials, the diffusion layer can include other materials as necessary. Other materials include, for example, conventionally known dispersants, surfactants, and antistatic agents for the purpose of increasing the hardness of the diffusion layer, suppressing curing shrinkage, and controlling the refractive index. , Silane coupling agents, thickeners, anti-coloring agents, colorants (pigments, dyes), antifoaming agents, leveling agents, flame retardants, UV absorbers, adhesion promoters, polymerization inhibitors, antioxidants, surface modification A quality agent, a lubricant, etc. can be included.

  The diffusion layer forming composition for forming the diffusion layer in the present disclosure can be obtained, for example, by uniformly mixing the above-described materials. Specifically, it can be obtained by a method using a known apparatus such as a paint shaker, a bead mill, a kneader, or a mixer.

  As a method of forming the diffusion layer in the present disclosure, for example, after applying the diffusion layer forming composition, heating is performed to dry the coating film on which the diffusion layer forming composition is applied. According to the method, the solvent is evaporated to dry the composition for forming the diffusion layer. Moreover, the diffusion layer forming composition is cured by irradiating light to the coating film formed by applying the diffusion layer forming composition to polymerize or crosslink the photopolymerizable compound to obtain a diffusion layer. Can do.

3. Organic EL Layer The organic EL layer in the present disclosure is a member that is disposed on the surface of the first electrode layer opposite to the transparent substrate and includes a light emitting layer.

  The organic EL layer in the present disclosure is a member having one or more organic layers including a light emitting layer. That is, the organic EL layer is a member including at least a light emitting layer, and is a member having a layer configuration of one or more organic layers. Usually, when forming an organic EL layer by a wet process, it is often composed of one or two organic layers because it is difficult to stack a large number of layers in relation to the solvent, It is possible to further increase the number of layers by devising organic materials or combining vacuum deposition methods.

  Examples of the layer constituting the organic EL layer other than the light emitting layer include a hole injection layer, an electron injection layer, a hole transport layer, and an electron transport layer. The hole transport layer may be integrated with the hole injection layer by imparting a hole transport function to the hole injection layer. In addition, the electron transport layer may be integrated with the electron injection layer by adding an electron transport function to the electron injection layer. Furthermore, as a layer which comprises an organic electroluminescent layer, the layer for preventing the penetration of a hole or an electron like a carrier block layer, and improving a recombination efficiency is mentioned.

  Hereinafter, each configuration of the organic EL layer in the present disclosure will be described.

(A) Light-Emitting Layer Examples of materials used for the light-emitting layer in the present disclosure include light-emitting materials such as dye-based materials, metal complex-based materials, and polymer-based materials.

  Examples of dye-based materials include cyclopentadiene derivatives, tetraphenylbutadiene derivatives, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, silole derivatives, thiophene ring compounds, pyridine Examples thereof include ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, and pyrazoline dimers.

  Examples of the metal complex-based material include aluminum quinolinol complex, benzoquinolinol beryllium complex, benzoxazole zinc complex, benzothiazole zinc complex, azomethyl zinc complex, porphyrin zinc complex, and eurobium complex. Or a metal complex having a rare earth metal such as Tb, Eu, or Dy and having a oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline structure, or the like as a ligand.

  Further, examples of the polymer material include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyvinylcarbazole, polyfluorene derivatives, polyquinoxaline derivatives, and copolymers thereof. Can be mentioned.

  The light emitting layer in the present disclosure may contain a doping agent for the purpose of improving the light emission efficiency and changing the light emission wavelength. Examples of the doping agent include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazoline derivatives, decacyclene, phenoxazone, quinoxaline derivatives, carbazole derivatives, fluorene derivatives, and the like. It is done.

  The thickness of the light emitting layer in the present disclosure is not particularly limited as long as it can provide a function of emitting light by providing a recombination field between electrons and holes, and is, for example, 1 nm or more. Moreover, it can be 500 nm or less.

  The light emitting layer in the present disclosure may be formed in a pattern so as to have light emitting portions of a plurality of colors such as red, green, and blue. Thereby, an organic EL element capable of color display can be obtained.

  As a method for forming a light emitting layer in the present disclosure, a general method for forming a light emitting layer can be adopted, and either a wet process or a dry process can be used. For example, vacuum deposition, printing, inkjet, die coating, spin coating, casting, dipping, bar coating, slit coating, blade coating, roll coating, gravure coating, gravure offset printing, Examples thereof include a coating method such as a flexographic printing method and a spray coating method, and a self-organizing method. In the present disclosure, the light emitting layer is preferably formed by a coating method. This is because the effects of the present disclosure can be made remarkable when light emission unevenness due to coating unevenness occurs.

(B) Hole injection layer and hole transport layer In the present disclosure, the hole transport layer may be integrated with the hole injection layer by imparting a hole transport function to the hole injection layer. . That is, the hole injection layer may have only a hole injection function, or may have both a hole injection function and a hole transport function.

  The material used for the hole injection layer is not particularly limited as long as the material can stabilize the injection of holes into the light emitting layer. In addition, phenylamine, starburst amine, phthalocyanine, vanadium oxide, molybdenum oxide, ruthenium oxide, aluminum oxide, titanium oxide and other oxides, amorphous carbon, polyaniline, polythiophene, polyphenylene vinylene derivatives, etc. can be used. . Specifically, bis (N-((1-naphthyl) -N-phenyl) benzidine (α-NPD), 4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) triphenylamine (m- MTDATA), poly (3,4-ethylenedioxythiophene) -polystyrene sulfonic acid (PEDOT-PSS), polyvinylcarbazole (PVCz) and the like.

  Further, the thickness of the hole injection layer is not particularly limited as long as the hole injection function and the hole transport function are sufficiently exhibited, but specifically, it is preferably 0.5 nm or more, It is preferable that it is 10 nm or more. In addition, the thickness of the hole injection layer is preferably 500 nm or less, and more preferably 200 nm or less.

  Since the method for forming the hole injection layer can be the same as the method for forming the light emitting layer described above, description thereof is omitted here.

(C) Electron Injection Layer and Electron Transport Layer In the present disclosure, the electron transport layer may be integrated with the electron injection layer by imparting an electron transport function to the electron injection layer. That is, the electron injection layer may have only an electron injection function, or may have both an electron injection function and an electron transport function.

  The material used for the electron injection layer is not particularly limited as long as the material can stabilize the injection of electrons into the light emitting layer. In addition to the compounds exemplified as the light emitting material of the light emitting layer, Aluminum lithium alloy, lithium fluoride, sodium fluoride, strontium, magnesium oxide, magnesium fluoride, strontium fluoride, calcium fluoride, barium fluoride, aluminum oxide, strontium oxide, calcium, polymethyl methacrylate, sodium polystyrene sulfonate, Examples include lithium, cesium, cesium fluoride, alkali metals, alkali metal halides, alkali metal organic complexes, and the like.

  Alternatively, a metal doped layer in which an alkali metal or alkaline earth metal is doped on an electron transporting organic material may be formed and used as an electron injection layer. Examples of the electron-transporting organic material include bathocuproin, bathophenanthroline, and phenanthroline derivatives. Examples of the metal to be doped include Li, Cs, Ba, and Sr. In addition, other examples include 8-hydroxyquinolinolato-lithium called Liq.

  The thickness of the electron transport layer is not particularly limited as long as the electron transport function is sufficiently exerted.

  Since the formation method of an electron carrying layer can be made the same as the formation method of the light emitting layer mentioned above, description here is abbreviate | omitted.

4). 1st electrode layer The 1st electrode layer in this indication is a transparent member arranged on one side of the transparent substrate mentioned below. In the organic EL element of the present disclosure, light is extracted from the first electrode layer side.

  The 1st electrode layer in this indication has predetermined transparency. The transparency of the first electrode layer is preferably such that the light emitted from the organic EL layer can be transmitted and display can be performed. For example, the transmittance in the visible light region is 80% or more. Is preferable, and 90% or more is more preferable.

  The first electrode layer may be an anode or a cathode. As a material of the first electrode layer, a material used for a general organic EL element can be used. For example, indium tin oxide called ITO, indium zinc oxide called IZO, indium oxide, tin oxide Etc. In addition, a material in which metal particles such as silver nanowires and metal nanowires such as copper nanowires are dispersed in a binder resin may be used as the first electrode layer.

  The thickness of the first electrode layer can be adjusted as appropriate according to the application of the organic EL element and the like, and is not particularly limited.

  The formation method of a 1st electrode layer can be suitably selected according to the structure of an organic EL element, and a 1st electrode layer may be formed in the whole surface of a transparent base material, and a 1st electrode layer is formed in pattern shape You may do it. Since the specific formation method of the first electrode layer can be the same as the general electrode formation method, description thereof is omitted here.

5. Second Electrode Layer The second electrode layer in the present disclosure is a member disposed on the surface of the organic EL layer opposite to the first electrode layer.

  The second electrode layer in the present disclosure may be an anode or a cathode. Examples of the material of the second electrode layer include metals such as Li, Na, Mg, Al, Ca, Ag, and In, or alloys containing one or more of these metals, such as MgAg, AlLi, AlCa, and AlMg. An alloy is mentioned. Among them, Al, Ag metal, or alloys containing Al and Ag such as MgAg, AlLi, AlCa, and AlMg are preferably used.

  The thickness of the second electrode layer is not particularly limited as long as it can function as the second electrode layer. For example, the thickness is preferably 10 nm or more, and more preferably 50 nm or more. . In addition, the thickness of the second electrode layer is preferably 1 μm or less, and more preferably in the range of 500 nm or less.

  The formation method of a 2nd electrode layer can be suitably selected according to the structure of an organic EL element. Since a specific method for forming the second electrode layer can be the same as a general electrode forming method, description thereof is omitted here.

6). Transparent substrate The transparent substrate in this indication is a member which supports the 1st electrode layer, organic EL layer, and 2nd electrode layer which were mentioned above.

  The transparent substrate in the present disclosure preferably has a predetermined transparency. The transparency of the transparent substrate is preferably such that the light emitted from the organic EL layer can be transmitted and displayed, and for example, the transmittance in the visible light region is 80% or more. Preferably, it is 90% or more. Here, the transmittance of the transparent substrate can be measured by a test method for the total light transmittance of a plastic-transparent material according to JIS K7361-1.

  The transparent substrate in the present disclosure may or may not have flexibility, and can be appropriately selected according to the use of the organic EL element. It is preferable. This is because flexibility can be imparted to the organic EL element of the present disclosure.

  Examples of the transparent base material include inflexible rigid materials such as quartz glass, Pyrex (registered trademark) glass, and synthetic quartz plates, or flexible materials such as resin films, optical resin plates, and thin glass. A flexible material having The transparent substrate in the present disclosure may be a laminate in which a barrier layer is formed on a resin film.

  The thickness of the transparent base material can be appropriately selected according to the type of material used for the transparent base material, the use of the organic EL element, and the like, for example, 0.005 mm or more, and 5 mm It can be as follows.

7). Other Member The organic EL element of this indication should just have each member mentioned above, and may have other members if needed. About another member, the member used for a general organic EL element is employable. For example, a sealing member that can be disposed so as to cover the organic EL element and prevent intrusion of moisture, a counter substrate that is disposed on the surface of the second electrode layer opposite to the organic EL layer, and the like Can be mentioned.

(1) Sealing member The sealing member in this indication is a member arranged so that an organic EL element may be covered.

  Examples of the material of the sealing member in the present disclosure include radical seal materials using resins such as various acrylates such as ester acrylate, urethane acrylate, epoxy acrylate, melamine acrylate, and acrylic resin acrylate, and urethane polyester, epoxy, and vinyl ether. Examples thereof include photo-curing resins such as cation-based sealing materials using resins such as thiol-ene addition-type resin-based sealing materials, and thermosetting resins.

  About the thickness of the sealing member, it can adjust suitably according to the use etc. of the organic EL element of this indication, and is not specifically limited.

  As a method for forming the sealing member, a conventional method can be used. For example, inkjet method, dispenser method, spin coating method, die coating method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, dip coating method, flexographic printing method, offset printing method, and Screen printing method etc. are mentioned.

(2) Opposing base material The opposing base material in the present disclosure is a member disposed on the surface of the second electrode layer opposite to the organic EL layer.

  Since the opposing base material in this indication is a member arrange | positioned on the surface on the opposite side to the light emission surface of an organic EL element, it may have transparency and does not need to have transparency.

  Examples of the material of the counter substrate in the present disclosure include inflexible rigid materials such as quartz glass, Pyrex (registered trademark) glass, and synthetic quartz plate, or resin films, optical resin plates, thin glass, and the like. Examples thereof include a flexible material having flexibility. In addition, the opposing base material in this indication may be the laminated body in which the barrier layer was formed in the resin film.

8). Application The application of the organic EL element of the present disclosure is not particularly limited, and can be applied to, for example, a display device, a lighting device, a light source, and the like. In the present disclosure, it is particularly preferable to apply to a lighting device. This is because the effect of reducing light emission unevenness can be made remarkable.

  Hereinafter, the present disclosure will be specifically described using examples and comparative examples.

[Example 1]
(Formation process of organic EL laminate)
Alkali-free glass was prepared as a transparent substrate. Next, a first electrode layer (material: indium silver oxide, thickness: 300 nm) was formed in a pattern on the transparent substrate. Thereafter, the transparent substrate on which the first electrode layer was formed was ultrasonically cleaned in the order of neutral detergent and ultrapure water, and then subjected to UV ozone treatment.

  Subsequently, a PEDOT / PSS aqueous dispersion (CLEVIOUS P AI4083 manufactured by Heraeus) was applied as a hole injecting and transporting layer on the obtained first electrode layer using a spin coating method in the air. Then, it heated at 200 degreeC and the conditions for 30 minutes in air | atmosphere using the hotplate, and obtained the 1st positive hole injection transport layer. The thickness of the first hole injection transport layer after heating was 20 nm.

Next, poly [(9,9-di-n-octylfluorenyl-2,7-diyl) -alt- (benzo [2,1,3] thiadiazole-4,8-diyl)] ( F8BT) was dissolved in xylene at a concentration of 1.2 wt%. The obtained ink was applied onto PEDOT by a spin coating method. Then, using a hot plate _{N 2} inert gas atmosphere _{(H 2 O, O 2} 1ppm or less), 0.99 ° C., by heating under the conditions of 30 minutes to remove the solvent to obtain a light-emitting layer. The thickness of the light emitting layer after heating was 80 nm.

Next, on the obtained light emitting layer, an electron injection layer (material: lithium fluoride (LiF), thickness: 0.5 nm) is hand-heated in the vacuum with a pressure of 1 × 10 ⁻⁴ Pa. A film was formed.

Next, on the obtained organic EL layer, a second electrode layer (material: Al) was formed by hand and after heating in a vacuum with a pressure of 1 × 10 ⁻⁴ Pa.

  Subsequently, it sealed in the glove box using an alkali free glass and UV curing epoxy adhesive, and produced the organic electroluminescent laminated body.

(Transparent layer and diffusion layer formation process)
Finally, a transparent layer (material: alkali-free glass, thickness: 0.7 mm) is provided on the transparent substrate side of the organic EL laminate, and further a diffusion layer (haze: 90%, thickness: 30 μm) on the transparent layer. ). Thus, the organic EL device of the present invention was produced. The obtained organic EL element was made to emit light in a light emitting area of 50 mm.

[Example 2]
A first transparent layer (material: alkali-free glass, thickness: 0.7 mm) is provided on the transparent substrate side of the organic EL laminate, and then a diffusion layer (haze: 90%, thickness) on the first transparent layer. 30 μm), and finally, a second transparent layer (material: non-alkali glass, thickness: 0.7 mm) was provided on the diffusion layer, and an organic EL device was produced in the same manner as in Example 1. did.

[Comparative Example 1]
An organic EL device was produced in the same manner as in Example 1 except that the transparent layer and the diffusion layer were not provided.

[Evaluation]
The organic EL elements (light emitting area: 50 mm □) obtained in Examples 1 and 2 and Comparative Example 1 were caused to emit light. As a result, in Comparative Example 1, light emission unevenness due to coating unevenness was noticeable. On the other hand, in Examples 1 and 2, light emission unevenness was reduced as compared with Comparative Example 1. 4A is a photograph of the light emitting area of Example 1, and FIG. 4B is a photograph of the light emitting area of Comparative Example 1.

DESCRIPTION OF SYMBOLS 1 ... Transparent base material 2 ... 1st electrode layer 3 ... Organic EL layer 4 ... 2nd electrode layer 5 ... Transparent layer 6 ... Diffusion layer 10 ... Organic EL element

Claims (2)

A transparent substrate;
A transparent first electrode layer on one side of the transparent substrate;
An organic electroluminescence layer on the surface of the first electrode layer opposite to the transparent substrate, comprising a light emitting layer;
A second electrode layer on a surface opposite to the first electrode layer of the organic electroluminescence layer;
A transparent layer on the surface of the transparent substrate opposite to the first electrode layer;
An organic electroluminescence device comprising: a diffusion layer on a surface of the transparent layer opposite to the transparent substrate.   The organic electroluminescent element according to claim 1, wherein the transparent layer has a heat dissipation member.