JP6859714B2 - Organic electroluminescence element - Google Patents

Description

Embodiments of the present disclosure relate to organic electroluminescence devices with a diffusion layer.

Organic electroluminescence elements have high visibility due to self-coloring, are excellent in impact resistance because they are all-solid-state displays unlike liquid crystal displays, have a high response speed, are less affected by temperature changes, and Attention is being paid to advantages such as a wide viewing angle. Hereinafter, organic electroluminescence may be abbreviated as organic EL.

The organic EL element usually has a structure in which a transparent base material, a transparent first electrode layer, an organic EL layer including a light emitting layer, and a second electrode layer are laminated in this order. In the organic EL element, light is extracted from the light emitting layer through the first electrode layer and the transparent base material. At this time, if unevenness or defects occur in the organic EL layer, the light emission becomes uneven and the organic EL element becomes uneven. There is a problem that the quality deteriorates.

Therefore, for example, Patent Documents 1 and 2 disclose a technique of providing a diffusion layer for diffusing light between a transparent base material and a first electrode layer to reduce light emission unevenness. Further, for example, Patent Document 3 discloses a technique of providing a diffusion layer on a surface of a transparent base material opposite to the first electrode layer to reduce light emission unevenness.

Japanese Unexamined Patent Publication No. 2012-69920 Japanese Unexamined Patent Publication No. 2012-178268 Japanese Unexamined Patent Publication No. 2014-229546

By the way, when a diffusion layer is provided in an organic EL element as in Patent Documents 1 to 3, it is possible to reduce slight light emission unevenness, but it is difficult to reduce even large light emission unevenness. Specifically, when the layer constituting the organic EL layer such as the light emitting layer is prepared by the coating method, the light emitting unevenness is caused by the coating unevenness, and the layer constituting the organic EL layer such as the light emitting layer is scratched in the manufacturing process. It is difficult to reduce the unevenness of light emission caused by the entry even by using the conventional technique of providing a diffusion layer.

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

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

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

In the present specification, when a certain structure such as a member or a certain area is "above (or below)" another structure such as another member or another area, unless otherwise specified. This includes not only the case of being directly above (or directly below) the other configuration, but also the case of being above (or below) the other configuration, that is, another configuration in between above (or below) the other configuration. Including the case where the element is included.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings and the like. However, the present disclosure can be implemented in many different embodiments and is not construed as limited to the description of the embodiments exemplified below. Further, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc. of each part as compared with the embodiment, but this is merely an example, and the interpretation of the present disclosure is used. It is not limited. Further, in the present specification and each figure, the same elements as those described above with respect to the above-mentioned figures may be designated by the same reference numerals, and detailed description thereof may be omitted as appropriate. Further, for convenience of explanation, the phrase "upper" or "lower" may be used for explanation, but the vertical direction may be reversed.

Hereinafter, the organic EL device according to one embodiment of the present disclosure will be described.

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

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

As shown in FIG. 5, the conventional organic EL element 10'is released from the transparent base material 1 side by providing the diffusion layer 6 on the surface of the transparent base material 1 opposite to the first electrode layer 2. It diffuses the light. When the inventor of the present disclosure examined a conventional organic EL element 10'with such a configuration, although slight light emission unevenness could be reduced, for example, a coating method of a layer constituting the organic EL layer such as a light emitting layer was applied. We discovered that it is not possible to sufficiently reduce relatively large light emission unevenness such as light emission unevenness caused by coating unevenness when created by the above method and light emission unevenness caused by scratches on the light emitting layer in the manufacturing process. did. Therefore, as a result of further studies by the present inventor of the present disclosure, as shown in the organic EL element 10 of the present disclosure shown in FIG. 1, a transparent layer 5 is provided between the transparent base material 1 and the diffusion layer 6. It was found that the above-mentioned problems can be solved by providing the above-mentioned problems. The reason for this is presumed to be as follows.

That is, when light is emitted from the surface light emitting source, the light flux travels while spreading radially. Therefore, the area illuminated by the light tends to increase in proportion to the distance from the surface emitting source. Then, when a 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 emitting source is increased by the amount corresponding to, it is possible to illuminate 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 the conventional organic EL element in which the transparent layer is not provided. Therefore, when a transparent layer is provided as in the organic EL element of the present disclosure, the light emission unevenness itself can be reduced, and the luminous flux passes through the diffusion layer in a state where the light emission unevenness itself is reduced. It is presumed that even a large light emission unevenness can be sufficiently reduced.

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

1. 1. Transparent layer The transparent layer in the present disclosure is a member arranged on a surface of a transparent base material opposite to the first electrode layer.

As shown in FIG. 1, the transparent layer in the present disclosure may be arranged on the surface of the transparent base material 1 opposite to the first electrode layer 2. Therefore, for example, as shown in FIG. 3, two or more transparent layers 6 may be arranged on the surface of the transparent base material 1 opposite to the first electrode layer 2. When two or more transparent layers are arranged, the diffusion layer may be arranged on the surface of at least one transparent layer opposite to the transparent base material. Among them, from the viewpoint of light diffusivity. Therefore, it is preferable that the diffusion layer is arranged on the surface opposite to the transparent layer on the most transparent substrate side. Further, the diffusion layer may be arranged on the surface of each transparent layer opposite to the transparent base material.

Since the transparent layer in the present disclosure is a member arranged on the light emitting surface side of the organic EL element, it is a transparent member having a predetermined transparency. Here, "having a predetermined transparency" means having transparency to the extent that it does not interfere with the visibility of the operator of the organic EL element of the present disclosure from the operation surface, unless otherwise specified. Therefore, "having a predetermined transparency" includes colorless transparency and colored transparency to the extent that visibility is not hindered, and the degree of light transmission is determined according to the application of the organic EL element of the present disclosure. Can be done.

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

The transparent layer in the present disclosure has a refractive index of the transparent base material and the diffusion layer, which are the upper and lower layers of the transparent layer, in order to prevent the light emitted from the organic EL layer from being totally reflected by the transparent layer. It is preferable to have a refractive index close to that of. For example, the difference in refractive index between the transparent substrate and the diffusion layer and the transparent layer is preferably in the range of ± 30%, particularly preferably in the range of ± 25%, and particularly in the range of ± 20%. Is preferable. The above-mentioned "difference in refractive index between the transparent base material and the diffusion layer and the transparent layer" refers to the difference in the refractive index between the transparent base material and the transparent layer and the difference in the refractive index between the diffusion layer and the transparent layer.

The transparent layer in the present disclosure may be, for example, a layer having the above-mentioned transparency, but among them, as described above, a layer having a refractive index close to that of the transparent base material and the diffusion layer is preferable. In the present disclosure, for example, as shown in FIG. 2A, the transparent layer 5 is a glass such as quartz, alkaline glass, non-alkali glass, thin glass thereof, polyethylene, polypropylene, polyethylene terephthalate, polymethacrylate, poly. Resins such as methyl methacrylate, polymethyl acrylate, polyester, polycarbonate, polyether sulfone, polyether ether ketone, polyvinyl fluoride, polyolefin, and fluororesin may be used, or as shown in FIG. 2 (b), they are transparent. 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. 1, and thus the description thereof will be omitted here.

In the present disclosure, when the transparent layer is an air layer, as shown in FIG. 2B, a frame-shaped support member 52 may be provided on the outer peripheral portion of the air layer 51, and although not shown, air may be provided. Support members may be provided in a pattern on the layer. The pattern shape of the support member at this time can be appropriately selected depending on the application of the organic EL element and the like, and is not particularly limited, but a shape that does not reduce the light extraction efficiency of the organic EL element is preferable. .. Further, the support member may have a mesh shape. When the support member has a mesh shape, 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 a predetermined transparency.

The thickness of the transparent layer in the present disclosure is such that a predetermined distance can be provided between the transparent base material and the diffusion layer, and the effect of the present disclosure of sufficiently reducing light emission unevenness can be exhibited. preferable. Specifically, the thickness of the transparent layer is preferably 0.01 mm or more, particularly preferably 0.05 mm or more, and particularly preferably 0.1 mm or more. The thickness of the transparent layer in the present disclosure is preferably 6 mm or less, particularly preferably 3 mm or less, and particularly preferably 1.5 mm or less. The thickness of the transparent layer here corresponds to, for example, 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. 2 (b).

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

(Heat dissipation member)
In the present disclosure, by having the heat radiating member, the heat accumulated inside the organic EL element due to the heat generated while driving the organic EL element can be dissipated to the outside of the organic EL element. Therefore, it is possible to suppress problems such as deterioration of each member constituting the organic EL element due to heat inside the organic EL element and a decrease in luminous efficiency of the organic EL element.

The heat radiating member in the present disclosure is a member containing a metal material. Above all, it is preferable that the member has a desired heat dissipation property. Examples of the metal material contained in the heat radiating member include aluminum, copper, copper alloy, phosphorus bronze, stainless steel (SUS), gold, gold alloy, nickel, nickel alloy, silver, silver alloy, tin, tin alloy, titanium, and so on. Examples thereof include iron, iron alloys, tin and molybdenum. Above all, it is preferable to use aluminum and copper for the heat radiating member in the present disclosure, and it is particularly preferable to use aluminum. This is because the above-mentioned metal material has excellent heat dissipation and is relatively inexpensive. Further, a metal paste may be used as the above-mentioned metal material.

The heat radiating member in the present disclosure may have an uneven shape on the surface. The surface area of the heat radiating member having an uneven shape on the surface is larger than that of the 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 surface of the heat radiating member and air increases, and more heat can be diffused to exhibit excellent heat radiating properties.

The uneven shape formed on the heat radiating member is preferably a shape capable of increasing the surface area of the heat radiating member and increasing the contact area with air. Examples of the shape of the convex portion in the concave-convex shape include a cone shape and a conical shape.

In the heat radiating member in the present disclosure, it is preferable that the surface on the transparent substrate side has light reflectivity. Since the light emitted from the organic EL layer and hitting the heat radiating member can be reflected back into the organic EL element, the light blocked by the heat radiating member can be reduced and the light extraction efficiency can be improved. it can. As a method of imparting light reflectivity to the surface of the heat radiating member on the transparent base material side, for example, a method of using a material having light reflectivity as the material of the heat radiating member or having light reflectivity on the surface of the transparent base material side. Examples thereof include a method of forming a light reflecting layer. As the material having light reflectivity, generally known materials such as metal materials can be mentioned, and thus the description thereof is omitted here.

Examples of the method for forming the heat radiating member in the present disclosure include a method of forming a metal vapor deposition film using a general vapor deposition method, a method of forming a metal plating film using a general plating method, and adhesion of an epoxy resin or the like. Examples thereof include a method of laminating metal foils via an agent.

(Other)
In the present disclosure, an adhesive, an adhesive or the like may be used to arrange the transparent layer and the heat radiating member on the surface of the transparent base material opposite to the first electrode layer. The transparent layer and the heat radiating member prepared in advance can be attached to the surface of the transparent base material opposite to the first electrode layer.

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

2. Diffusion layer The diffusion layer in the present disclosure is a member arranged on the surface of the transparent layer opposite to the transparent base material.

In the present disclosure, as shown in FIG. 1, the diffusion layer 6 may be arranged at least on the surface of the transparent layer 5 opposite to the transparent base material 1. Therefore, for example, as shown in FIG. 3, the diffusion layer 6 is arranged on the surface of the transparent layer 5 on the side opposite to the transparent base material 1 and on the surface of the transparent layer 5 on the transparent base material 1 side. It may have been done. In the present disclosure, when two or more transparent layers are arranged on the surface of the transparent base material opposite to the first electrode layer, at least one of the transparent base materials is the transparent base material. It suffices if the diffusion layer is arranged on the opposite surface, but from the viewpoint of light diffusivity, the diffusion layer is arranged on the surface of the transparent layer on the most transparent substrate side opposite to the transparent substrate. It is preferable that it is. Further, in the present disclosure, it is preferable that the diffusion layer is arranged on the surface of each transparent layer opposite to the transparent base material.

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

The diffusion layer in the present disclosure may be a member having a function of diffusing light, and above all, a member having a predetermined haze value as described above is preferable. For example, a member in which light diffusing 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, etc., and a diffusible film having a diffusing function. And diffusible sheets. When, for example, a paper containing fibers such as Japanese paper, a diffusible film having a diffusing function, a diffusing sheet, or the like is used as the diffusing layer, the diffusing layer can be directly attached to the transparent layer. In the present disclosure, it is particularly preferable that the member is a member in which light diffusing particles are dispersed in a binder component. Further, the diffusion layer in the present disclosure may have a design property such as a shade of color, if 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 mentioned here means a thin and flat molded paper while entwining plant fibers, etc., and according to the Japanese Industrial Standards (JIS), it is "manufactured by sticking plant fibers and other fibers". It is defined. Therefore, the paper in the present disclosure includes, in addition to Japanese paper, those defined by the above JIS, that is, those molded using fibers of various raw materials such as plant-derived raw materials and synthetic resins.

When the diffusing layer in the present disclosure contains a binder component and light diffusing particles, it is preferable that there is a predetermined difference in refractive index between the binder component and the light diffusing particles. For example, the difference in refractive index is preferably in the range of 0.01 or more and 1 or less, and particularly preferably in the range of 0.1 or more and 0.5 or less. When the difference in refractive index between the binder component and the light diffusing particles is within the above range, excellent light diffusivity can be obtained, and the effect of reducing light emission unevenness 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 declination method, the declination analysis, the mode line method, the ellipsometry method, or the like.

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

An organic material or an inorganic material can be used as the light diffusing particles used in the diffusing layer. Examples of the organic material used for the light diffusing particles include polyester, polystyrene, melamine resin, (meth) acrylic resin, acrylic-styrene copolymer resin, silicone resin, benzoguanamine resin, benzoguanamine / formaldehyde condensation resin, polycarbonate, polyethylene, and the like. Examples thereof 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 for the diffusion layer include a polymer (crosslinked product) of a photopolymerizable compound, a solvent-drying resin, a thermosetting resin, and the like, and one or more of these resins may be used. it can.

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

The solvent-drying resin used as a binder component is a resin such as a thermoplastic resin that forms a film only by drying a solvent added to adjust the solid content at the time of coating. As the solvent-drying resin, for example, a general thermoplastic resin can be used. Examples of the thermoplastic resin include styrene resin, (meth) acrylic resin, vinyl acetate resin, vinyl ether resin, halogen-containing resin, alicyclic olefin resin, polycarbonate resin, polyester resin, and polyamide resin. , 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, and melamine-urea. Examples thereof include cocondensation resin, silicon resin, and polysiloxane resin.

The diffusion layer may contain other materials, if necessary, in addition to the materials described above. 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 agent, thickener, color inhibitor, colorant (pigment, dye), defoamer, leveling agent, flame retardant, ultraviolet absorber, adhesive, adhesive, polymerization inhibitor, antioxidant, surface modification It can contain a pledge agent, an anti-slip agent, and the like.

The composition for forming a diffusion layer for forming a diffusion layer in the present disclosure can be obtained, for example, by uniformly mixing the above-mentioned materials. Specifically, it can be obtained by a method using a known device 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 composition for forming a diffusion layer, the coating film to which the composition for forming a diffusion layer is applied is heated to dry, and various known methods are used. By the method, the solvent is evaporated to dry the diffusion layer forming composition. Further, the coating film formed by applying the diffusion layer forming composition is irradiated with light to polymerize or crosslink the photopolymerizable compound to cure the diffusion layer forming composition to obtain a diffusion layer. Can be done.

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

The organic EL layer in the present disclosure is a member having one or a plurality of 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 structure of one or more organic layers. Usually, when an organic EL layer is formed by a wet process, it is difficult to stack a large number of layers in relation to a solvent, so that the organic EL layer is often composed of one or two organic layers. By devising an organic material or combining a vacuum vapor deposition method, it is possible to further increase the number of layers.

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. Further, the electron transport layer may be integrated with the electron injection layer by imparting an electron transport function to the electron injection layer. Further, examples of the layer constituting the organic EL layer include a layer for preventing the penetration of holes or electrons and increasing the recombination efficiency, such as a carrier block layer.

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

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

Examples of the dye-based material include cyclopentadiene derivatives, tetraphenylbutadiene derivatives, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, silol derivatives, thiophene ring compounds, and pyridines. Examples thereof include ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifmanylamine derivatives, oxaziazole dimers, pyrazoline dimers and the like.

Examples of the metal complex material include aluminum quinolinol complex, benzoquinolinol berylium complex, benzoxazole zinc complex, benzothiazole zinc complex, azomethylzinc complex, porphyrin zinc complex, eurobium complex and the like, and Al, Zn, Be as the central metal. Or, a metal complex having a rare earth metal such as Tb, Eu, Dy and having an oxadiazole, thiadiazol, phenylpyridine, phenylbenzoimidazole, quinoline structure or the like as a ligand can be mentioned.

Further, as the polymer-based material, for example, a polyparaphenylene vinylene derivative, a polythiophene derivative, a polyparaphenylene derivative, a polysilane derivative, a polyacetylene derivative, a polyvinylcarbazole, a polyfluorene derivative, a polyquinoxaline derivative, and a copolymer thereof are used. Can be mentioned.

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

The thickness of the light emitting layer in the present disclosure is not particularly limited as long as it can provide a field for recombination of electrons and holes and exhibit a function of emitting light, and is, for example, 1 nm or more. And 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 the light emitting layer in the present disclosure, a general method for forming the light emitting layer can be adopted, and either a wet process or a dry process can be used. For example, vacuum deposition method, printing method, inkjet method, die coating method, spin coating method, casting method, dipping method, bar coating method, slit coating method, blade coating method, roll coating method, gravure coating method, gravure offset printing method, Examples include a coating method such as a flexographic printing method and a spray coating method, and a self-assembling method. In the present disclosure, it is preferable that the light emitting layer is formed by a coating method. This is because the effect of the present disclosure can be made remarkable when light emission unevenness occurs due to coating unevenness.

(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 the hole injection function, or may have both the hole injection function and the hole transport function.

The material used for the hole injection layer is not particularly limited as long as it can stabilize the injection of holes into the light emitting layer, and the compound exemplified for the light emitting material of the light emitting layer is used. In addition, phenylamine-based, starburst-type amine-based, phthalocyanine-based, vanadium oxide, molybdenum oxide, ruthenium oxide, aluminum oxide, oxides such as titanium oxide, amorphous carbon, polyaniline, polythiophene, polyphenylene vinylene derivatives and the like 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.

The thickness of the hole injection layer is not particularly limited as long as it sufficiently exhibits the hole injection function and the hole transport function, but specifically, it is preferably 0.5 nm or more, and above all, it is preferable. It is preferably 10 nm or more. 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, the description here is omitted.

(C) Electron-injection layer and electron-transporting layer In the present disclosure, the electron-transporting layer may be integrated with the electron-injecting layer by imparting an electron-transporting function to the electron-injecting 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 it can stabilize the injection of electrons into the light emitting layer, and in addition to the compounds exemplified for the light emitting material of the light emitting layer, Lithium aluminum alloy, lithium fluoride, sodium fluoride, strontium, magnesium oxide, magnesium fluoride, strontium fluoride, calcium fluoride, barium fluoride, aluminum oxide, strontium oxide, calcium, polymethylmethacrylate, sodium polystyrenesulfonate, Examples thereof include alkali metals such as lithium, cesium, and cesium fluoride, halides of alkali metals, and organic complexes of alkali metals.

Further, it is also possible to form a metal-doped layer in which an alkali metal or an alkaline earth metal is doped in an electron-transporting organic material, and use this as an electron-injected layer. Examples of the electron-transporting organic material include vasocuproin, vasofenanthroline, and phenanthroline derivatives, and examples of the metal to be doped include Li, Cs, Ba, Sr, and the like. In addition, 8-hydroxyquinolinolato-lithium called Liq can also be mentioned.

The thickness of the electron transport layer is not particularly limited as long as it is thick enough to exhibit the electron transport function.

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

4. First Electrode Layer The first electrode layer in the present disclosure is a transparent member arranged on one surface of a transparent base material described later. In the organic EL element of the present disclosure, light is extracted from the first electrode layer side.

The first electrode layer in the present disclosure has a predetermined transparency. The transparency of the first electrode layer is preferably such that light emitted from the organic EL layer can be transmitted for display. 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 the material of the first electrode layer, a material used for a general organic EL device can be used. For example, indium tin oxide called ITO, indium zinc oxide called IZO, indium oxide, tin oxide can be used. And so on. Further, a layer 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 appropriately adjusted according to the application of the organic EL element and the like, and is not particularly limited. Therefore, the description thereof is omitted here.

The method for forming the first electrode layer can be appropriately selected according to the configuration of the organic EL element, the first electrode layer may be formed on the entire surface of the transparent base material, and the first electrode layer is formed in a pattern. You may. Since the specific method for forming the first electrode layer can be the same as the general method for forming the electrode, the description here is omitted.

5. Second Electrode Layer The second electrode layer in the present disclosure is a member arranged on a 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. The material of the second electrode layer includes, for example, 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. Alloys can be mentioned. Among them, metals of Al and Ag, 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 exhibit the function as the second electrode layer, but is preferably 10 nm or more, and more preferably 50 nm or more, for example. .. The thickness of the second electrode layer is preferably 1 μm or less, and more preferably 500 nm or less.

The method for forming the second electrode layer can be appropriately selected according to the configuration of the organic EL element. Since the specific method for forming the second electrode layer can be the same as the general method for forming the electrode, the description here is omitted.

6. Transparent base material The transparent base material in the present disclosure is a member that supports the above-mentioned first electrode layer, organic EL layer, and second electrode layer.

The transparent substrate in the present disclosure preferably has a predetermined transparency. The transparency of the transparent base material is preferably such that light emitted from the organic EL layer can be transmitted for display. For example, the transmittance in the visible light region is 80% or more. It is preferably 90% or more, and more preferably 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 base material in the present disclosure may or may not have flexibility, and can be appropriately selected depending on the use of the organic EL element, and among them, it has flexibility. Is preferable. This is because the organic EL element of the present disclosure can be imparted with flexibility.

As the material of the transparent base material, for example, a rigid material having no flexibility such as quartz glass, Pyrex (registered trademark) glass, and synthetic quartz plate, or a flexible material such as a resin film, an optical resin plate, and thin glass. A flexible material having the above can be mentioned. The transparent base material 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 depending on the type of material used for the transparent base material, the application of the organic EL element, etc., but can be, for example, 0.005 mm or more, and 5 mm. It can be as follows.

7. Other Members The organic EL element of the present disclosure may have each of the above-mentioned members, and may have other members as needed. As for other members, members used for general organic EL elements can be adopted. For example, a sealing member which is arranged so as to cover the organic EL element and can prevent the invasion of moisture, an opposing base material which is arranged 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 the present disclosure is a member arranged so as to cover the organic EL element.

Examples of the material of the sealing member in the present disclosure include various acrylates such as ester acrylate, urethane acrylate, epoxy acrylate, melamine acrylate and acrylic resin acrylate, radical sealing materials using resins such as urethane polyester, epoxy and vinyl ether. Examples thereof include a cationic sealing material using a resin such as thiol-ene, a photocurable resin such as a thiol-ene addition type resin-based sealing material, and a heat-curable resin.

The thickness of the sealing member can be appropriately adjusted according to the application of the organic EL element of the present disclosure, and is not particularly limited.

Examples of the method for forming the sealing member include conventional methods. 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 and the like can be mentioned.

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

Since the opposing base material in the present disclosure is a member arranged on the surface opposite to the light emitting surface of the organic EL element, it may or may not have transparency.

Examples of the material of the opposing base material 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. The opposing base material in the present disclosure may be a laminate in which a barrier layer is formed on a resin film.

8. Applications The applications of the organic EL element of the present disclosure are not particularly limited, but can be applied to, for example, display devices, lighting devices, light sources, and the like. In the present disclosure, it is particularly preferable to apply it 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 with reference to Examples and Comparative Examples.

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

Subsequently, as the hole injection transport layer, a PEDOT / PSS aqueous dispersion (CLEVIOUS PAI4083 manufactured by Heraeus) was applied onto the obtained first electrode layer in the atmosphere by a spin coating method. Then, it was heated in the air at 200 ° C. for 30 minutes using a hot plate to obtain a first hole injection transport layer. The thickness of the first hole injection transport layer after heating was 20 nm.

Next, as a light emitting layer, 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, _{the solvent was removed by heating with a hot plate under the conditions of N 2} inert gas atmosphere (H ₂ O, O ₂ 1 ppm or less) at 150 ° C. for 30 minutes to obtain a light emitting layer. The thickness of the light emitting layer after heating was 80 nm.

Next, an electron-injected layer (material: lithium fluoride (LiF), thickness: 0.5 nm) was placed on the obtained light-emitting layer in ^{a vacuum at a pressure of 1 × 10 -4} Pa by a manual thermal thin-film deposition method. A film was formed.

Next, a second electrode layer (material: Al) was formed on the obtained organic EL layer by a thermal thin-film deposition method in a vacuum ^{having a pressure of 1 × 10 -4 Pa.}

Next, in the glove box, it was sealed with non-alkali glass and a UV curable epoxy adhesive to prepare an organic EL laminate.

(Step of forming transparent layer and diffusion layer)
Finally, a transparent layer (material: non-alkali glass, thickness: 0.7 mm) is provided on the transparent base material side of the organic EL laminate, and a diffusion layer (haze: 90%, thickness: 30 μm) is further provided on the transparent layer. ) Was provided. In this way, 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: non-alkali glass, thickness: 0.7 mm) is provided on the transparent base material side of the organic EL laminate, and then a diffusion layer (haze: 90%, thickness) is provided on the first transparent layer. : 30 μm) was provided, and finally, an organic EL element was produced in the same manner as in Example 1 except that a second transparent layer (material: non-alkali glass, thickness: 0.7 mm) was provided on the diffusion layer. 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 element (light emitting area: 50 mm □) obtained in Examples 1 and 2 and Comparative Example 1 was made to emit light. As a result, in Comparative Example 1, light emission unevenness due to coating unevenness was remarkably observed. On the other hand, in Examples 1 and 2, light emission unevenness could be reduced as compared with Comparative Example 1. Note that FIG. 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.

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 (1)

With a transparent base material
A transparent first electrode layer on one surface of the transparent substrate and
An organic electroluminescence layer containing a light emitting layer and on a surface of the first electrode layer opposite to the transparent base material,
The second electrode layer on the surface of the organic electroluminescence layer opposite to the first electrode layer,
A transparent layer on the surface of the transparent substrate opposite to the first electrode layer,
The transparent layer has a diffusion layer on the surface opposite to the transparent base material, and has a diffusion layer.
The transparent layer is an air layer, is provided between the diffusion layer and the transparent substrate are disposed heat radiation member functions as a support member, the heat dissipation member is Ri member der containing a metal material,
The surface of the transparent base material side of the heat radiating member, that have a light reflectivity, an organic electroluminescent device.

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