JP6201311B2 - Surface light emitter and manufacturing method thereof - Google Patents

Description

  The present invention relates to a surface light emitter and a method for manufacturing the surface light emitter.

  Organic EL (electroluminescence) light-emitting elements are expected to be used for next-generation illumination that replaces flat panel displays, fluorescent lamps, and the like.

  The structure of the organic EL light emitting element is diversified from a simple structure in which an organic thin film serving as a light emitting layer is sandwiched between two films to a multilayer structure. Examples of the latter multilayered structure include a structure in which a positive hole transport layer, a light emitting layer, an electron transport layer, and a cathode are laminated on an anode. The layers sandwiched between the anode and the cathode are all composed of organic thin films, and the thickness of each organic thin film is very thin.

  Organic EL light-emitting elements are difficult to form uniformly over a large area due to their thinness, and it is very difficult to achieve the production of a large-area surface light emitter with only one organic EL light-emitting element. Therefore, in order to manufacture a large area surface light emitter using an organic EL light emitting element, it is common to achieve a large area by connecting a plurality of organic EL light emitting elements. There is a problem that the joint portion of the light does not emit light or becomes dark.

  In order to solve the above-mentioned problem, for example, Patent Document 1 proposes a surface light emitter in which light scattering means is provided between end surfaces of a transparent substrate and the joint portion of the organic EL light emitting element is suppressed from being darkened. Yes. Further, Patent Document 2 proposes a surface light emitter that uses a reflector or a scattering layer to increase the overall light emission amount.

JP 2005-183352 A JP 2004-2001148 A

  However, the surface light emitters proposed in Patent Document 1 and Patent Document 2 scatter the light emitted from the organic EL light emitting elements, and although the improvement of the darkness of the joints of the organic EL light emitting elements is seen, the improvement Is insufficient, and it cannot be said that the entire surface light emitter emits light uniformly.

  Accordingly, an object of the present invention is to improve the darkness of the joints of organic EL light-emitting elements in a surface light-emitting body using a plurality of organic EL light-emitting elements, so that the entire surface light-emitting body emits light uniformly and has a large area. Is to provide.

The present invention is a surface light emitter in which a plurality of organic EL light emitting elements are arranged on the light incident surface side of a substrate, and a diffusing means is provided in the gap between the organic EL light emitting elements , and the diffusing means is on the side opposite to the substrate. The present invention relates to a surface light emitter that is a diffusing unit having a concave curved surface, or a diffusing unit having a concavo-convex structure on the surface opposite to the substrate .

  The surface light emitter of the present invention can emit light uniformly over the entire surface light emitter, and the area can be increased. Moreover, according to the manufacturing method of the present invention, a large area surface light emitter can be obtained using the organic EL light emitting element, and the obtained large area surface light emitter emits light uniformly.

It is typical sectional drawing which shows an example of the surface light-emitting body of this invention. It is a typical sectional view showing an example of an organic EL light emitting element. It is typical sectional drawing which shows an example of the shape and structure of a spreading | diffusion means. It is a typical perspective view which shows an example of a prism sheet. It is a typical perspective view which shows an example of a cylindrical lens sheet. FIG. 4 is a schematic view of an example of a microlens sheet viewed from above and a schematic perspective view showing an example of a microlens.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these drawings.

(Surface emitter 10)
An example of the surface light emitter 10 of the present invention is shown in FIG.
In the surface light emitter 10 of the present invention, a light extraction layer 14 is disposed on the light emitting surface side of the substrate 11, and a plurality of organic EL light emitting elements 12 are disposed on the light incident surface side of the substrate 11. It has diffusion means 13.

(Substrate 11)
The substrate 11 is not particularly limited as long as it has a high light transmittance in the visible light wavelength region (approximately 400 to 700 nm) emitted from the organic EL light emitting element 12.
Examples of the shape of the substrate 11 include a film and a sheet.
The thickness of the substrate 11 is preferably 0.1 to 100 mm, and more preferably 0.2 to 50 mm. When the thickness of the substrate 11 is 0.1 mm or more, the handleability of the surface light emitter is excellent. Moreover, when the thickness of the substrate 11 is 100 mm or less, the luminance of the surface light emitter is excellent, and the surface light emitter is reduced in weight.

  Examples of the material of the substrate 11 include glass; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; acrylic resins such as polymethyl methacrylate; polycarbonate resins; polyvinyl chloride resins; styrene-based materials such as polystyrene and ABS resins. Resins; Cellulose resins such as diacetyl cellulose and triacetyl cellulose; Polyolefin resins such as polyethylene and polypropylene; Polyimide resins; Aramid resins and the like. Among these materials of the substrate 11, glass and acrylic resin are preferable because of the high light transmittance in the visible light wavelength region and the brightness of the surface light emitter, and the substrate 11 has excellent dimensional stability and heat resistance. Since it is excellent in the handleability of a light-emitting body, glass is more preferable.

  Since the refractive index of the material of the substrate 11 is excellent in the luminance of the surface light emitter, the refractive index is preferably close to the material of the organic EL light emitting element substrate 21 and the diffusing means 13, and preferably 1.30 to 2.00. 1.35 to 1.90 is more preferable, and 1.40 to 1.80 is still more preferable.

The substrate 11 may include fine particles as necessary in order to make the luminance of the surface light emitter more uniform.
Examples of the fine particles include fine particles exemplified as the fine particles of the diffusing means 13 (c) made of a resin containing fine particles described later. The volume average particle diameter of the preferable fine particles and the shape of the preferable fine particles are also the same as the fine particles of the diffusion means 13 (c) made of a resin containing the fine particles described later.

(Adhesive layer 15)
An adhesive layer 15 may be provided on the light incident surface side of the substrate 11 as necessary in order to fix the organic EL light emitting element 12 and the diffusing means 13.
Examples of the material of the pressure-sensitive adhesive layer 15 include a known pressure-sensitive adhesive, a known pressure-sensitive adhesive sheet, a known adhesive, a known adhesive sheet, a known optical adhesion sheet, a known optical adhesion liquid such as Cargill standard refraction liquid, and the like. It is done. Among these materials for the pressure-sensitive adhesive layer 15, a material that can be optically contacted, such as a known optical contact sheet or a known optical contact liquid, is preferable because of the excellent luminance of the surface light emitter.
Similarly, in order to form a surface light emitter on the light emitting surface side of the organic EL light emitting element 12, the light incident surface side of the light extraction layer 14, the boundary surface between the organic EL light emitting element 12 and the diffusing means 13, and the like. A similar adhesive layer 15 may be provided, and since the brightness of the surface light emitter is excellent, a material that can be optically contacted, such as a known optical contact sheet or a known optical contact liquid, is used as the material of the adhesive layer 15. It is preferable.
Further, instead of providing the adhesive layer 15, an easy adhesion process may be performed on the surface of the substrate 11, the light extraction layer 14, or the like. Further, the light extraction layer 14 may be formed directly on the light emitting surface side of the substrate 11.
Here, optical contact means a state in which light-transmitting objects are in close contact with each other without forming an air layer therebetween. In general, the surface of a film or sheet has a fine uneven structure. By filling this fine concavo-convex structure with a material having a close refractive index that can be optically adhered instead of air, it is possible to suppress a decrease in luminance of the surface light emitter, and thus an adhesive that can be optically adhered between the respective layers. It is preferable to provide the layer 15.

(Organic EL light emitting device 12)
An example of the organic EL light emitting device 12 is shown in FIG.
In the organic EL light emitting device 12 shown in FIG. 2, an organic EL light emitting device substrate 21, a first electrode 22, a light emitting layer 23, and a second electrode 24 are sequentially laminated from the light emitting surface side.
Hereinafter, although the organic EL light emitting element 12 shown in FIG. 2 is demonstrated, it is not limited to the organic EL light emitting element 12 shown in FIG.

(Organic EL light emitting device substrate 21)
The organic EL light emitting element substrate 21 is not particularly limited as long as it has a high light transmittance in the visible light wavelength region (approximately 400 to 700 nm) emitted from the light emitting layer 23.
Examples of the shape of the organic EL light emitting element substrate 21 include a foil, a film, and a sheet.
The thickness of the organic EL light emitting element substrate 21 is preferably 0.1 to 20 mm, and more preferably 0.2 to 10 mm. When the thickness of the organic EL light emitting element substrate 21 is 0.1 mm or more, the handleability of the organic EL light emitting element 12 is excellent. Moreover, when the thickness of the organic EL light emitting element substrate 21 is 20 mm or less, the surface light emitter is excellent in luminance and the surface light emitter is reduced in weight.

  Examples of the material of the organic EL light emitting device substrate 21 include the materials exemplified for the substrate 11. Among these materials of the organic EL light emitting element substrate 21, glass and acrylic resin are preferable because of high light transmittance in the visible light wavelength region and excellent luminance of the surface light emitter, and dimensional stability of the organic EL light emitting element substrate 21. Glass is more preferable because it is excellent in heat resistance and heat resistance, and is excellent in handleability of the surface light emitter.

  The refractive index of the material of the organic EL light emitting element substrate 21 is preferably a refractive index close to the material of the substrate 11 and the diffusing means 13, and preferably 1.30 to 2.00, because the luminance of the surface light emitter is excellent. 1.35 to 1.90 is more preferable, and 1.40 to 1.80 is still more preferable.

(First electrode 22)
The first electrode 22 may be an anode or a cathode, but is usually an anode.
Examples of the material of the first electrode 22 include ITO (indium tin oxide), IZO (indium zinc oxide), FTO (fluorine-doped tin oxide), GZO (gallium-doped zinc oxide), AZO (aluminum-doped zinc oxide), and ATO. (Antimony-doped tin oxide), indium oxide, zinc oxide, tin oxide, titanium oxide and the like. These materials for the first electrode 22 may be used alone or in combination of two or more. Among these materials for the first electrode 22, ITO, IZO, FTO, GZO, AZO, ATO, zinc oxide, and tin oxide are preferable because of excellent transparency and conductivity and excellent luminance of the surface light emitter. , IZO and FTO are more preferable.

The first electrode 22 may be a single layer or two or more layers.
The thickness of the first electrode 22 is preferably 10 nm to 2 mm, and more preferably 50 nm to 1 mm. When the thickness of the first electrode 22 is 10 nm or more, the conductivity is excellent. Moreover, it is excellent in transparency as the thickness of the 1st electrode 22 is 1 mm or less.
The thickness of the first electrode 22 can be measured by a step, surface roughness, and fine shape measuring device.

(Light emitting layer 23)
The light emitting layer 23 is a layer containing a light emitting material of an organic compound.
As a light-emitting material of an organic compound of the light-emitting layer 23, for example, a carbazole derivative (4,4′-N, N′-dicarbazole-diphenyl or the like) that is a host compound of a phosphorescent compound and an iridium complex (Tris (2- Phenylpyridine) iridium doped metal complexes of 8-hydroxyquinoline or derivatives thereof (tris (8-hydroxyquinoline) aluminum, etc.); other known light emitting materials.
The light emitting layer 23 may include a hole transporting material to be described later, an electron transporting material to be described later, and the like in addition to the light emitting material of the organic compound.

The light emitting layer 23 may be a single layer or two or more layers. For example, when the surface light emitter is used as white organic EL illumination, the light emitting layer 23 may have a laminated structure including a blue light emitting layer, a green light emitting layer, and a red light emitting layer.
The thickness of the light emitting layer 23 is preferably 1 nm to 3 μm, and more preferably 10 nm to 2 μm. When the thickness of the light emitting layer 23 is 1 nm or more, the luminance of the surface light emitter is excellent. Moreover, the brightness nonuniformity of a surface light emitter can be suppressed as the thickness of the light emitting layer 23 is 3 micrometers or less.
The thickness of the light emitting layer 23 can be measured by a step, surface roughness, and fine shape measuring device.

(Second electrode 24)
The second electrode 24 may be a cathode or an anode, but is usually a cathode.
Examples of the material of the second electrode 24 include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, and terbium. Metals such as ytterbium; alloys combining two or more of these metals; metal salts such as fluorides of these metals; one or more of these and gold, silver, platinum, copper, manganese, titanium, cobalt , An alloy with one or more of nickel, tungsten, and tin. Examples of the alloy include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, and calcium-aluminum alloy.

The second electrode 24 may be a single layer or two or more layers.
The thickness of the second electrode 24 is preferably 5 nm to 3 mm, and more preferably 10 nm to 2 mm. When the thickness of the second electrode 24 is 5 nm or more, the conductivity is excellent. Further, when the thickness of the second electrode 24 is 3 mm or less, the durability is excellent.
The thickness of the second electrode 24 can be measured by a step / surface roughness / fine shape measuring device.

(Other functional layers)
If necessary, another functional layer may be provided between the first electrode 22 and the light emitting layer 23 or between the light emitting layer 23 and the second electrode 24.
Examples of other functional layers include a hole injection layer, a hole transport layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

The hole injection layer is a layer containing a hole injection material.
Examples of the hole injection material include transition metal oxides such as molybdenum oxide and vanadium oxide; copper phthalocyanine; an organic polymer having conductivity; and other known organic hole injection materials.
In the case of a transition metal oxide, the thickness of the hole injection layer is preferably 2 to 20 nm, and more preferably 3 to 10 nm. In the case of an organic hole injection material, the thickness of the hole injection layer is preferably 1 to 100 nm, and more preferably 10 to 50 nm.

The hole transport layer is a layer containing a hole transport material.
Examples of the hole transporting material include triphenyldiamines (4,4′-bis (m-tolylphenylamino) biphenyl and the like); and other known hole transporting materials.
1-100 nm is preferable and, as for the thickness of a positive hole injection layer, 10-50 nm is more preferable.

The hole blocking layer is a layer containing a hole blocking material.
Examples of the hole blocking material include 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline); and other known hole blocking materials.
1-100 nm is preferable and, as for the thickness of a positive hole injection layer, 5-50 nm is more preferable.

The electron transport layer is a layer containing an electron transport material.
Examples of the electron transporting material include a metal complex of 8-hydroxyquinoline or a derivative thereof; an oxadiazole derivative; and other known electron transporting materials.
1-100 nm is preferable and, as for the thickness of an electron carrying layer, 10-50 nm is more preferable.

The electron injection layer is a layer containing an electron injection material.
Examples of the electron injection material include alkali metal compounds (such as lithium fluoride); alkaline earth metal compounds (such as magnesium fluoride); metals (such as strontium); and other known electron injection materials.
The thickness of the electron injection layer is preferably 0.1 to 50 nm, and more preferably 0.2 to 10 nm.
The thicknesses of these other functional layers can be measured with a step, surface roughness, and fine shape measuring device.

The 1st electrode 22, the light emitting layer 23, the 2nd electrode 24, another functional layer, etc. can be laminated | stacked by a well-known lamination | stacking method.
Examples of the lamination method include a sputtering method, a vapor deposition method, and an ion plating method. These lamination methods may be appropriately selected depending on the layer to be laminated, the characteristics of the layer to be laminated, and the like.
Moreover, before these lamination | stacking, in order to improve the adhesiveness between layers, you may perform processes, such as an ultraviolet ozone process, a plasma process, and a corona treatment, as needed.

(Diffusion means 13)
The diffusing means 13 is disposed in the gap between the organic EL light emitting elements 12 and emits light emitted from the side surface of the organic EL light emitting element 12 to the substrate 11 or reflects from the substrate 11 etc. from the light emitting surface side. The purpose is to reflect the incident light again and emit it to the substrate 11.
The diffusing unit 13 is not particularly limited as long as it achieves the above-mentioned object. For example, the diffusing unit has a concave curved surface on the surface opposite to the substrate, and has a concavo-convex structure on the surface opposite to the substrate. Means, diffusion means made of resin containing fine particles, known diffusion means, and the like. Among these diffusing means 13, since the brightness of the surface light emitter is excellent, a diffusing means having a concave curved surface on the surface opposite to the substrate, a diffusing means having a concavo-convex structure on the surface opposite to the substrate, and fine particles are used. Diffusion means made of resin is preferable, diffusion means having a concave curved surface on the surface opposite to the substrate, diffusion means having a concavo-convex structure on the surface opposite to the substrate is more preferable, and on the surface opposite to the substrate Diffusion means having an uneven structure is more preferable.

  The thickness of the diffusing means 13 is preferably about the same as the thickness of the organic EL light emitting element 12 because it efficiently captures light emitted from the side surface of the organic EL light emitting element 12. Is preferable, and 0.2 to 10 mm is more preferable.

  The refractive index of the material of the diffusing unit 13 is preferably a refractive index close to that of the substrate 11 or the organic EL light-emitting element substrate 21 because of excellent luminance of the surface light emitter, preferably 1.30 to 2.00. .35 to 1.90 is more preferable, and 1.40 to 1.80 is more preferable.

(Diffusion means 13 (a) having a concave curved surface)
Diffusion means 13 (a) having a concave curved surface on the surface opposite to the substrate (hereinafter simply referred to as “diffusion means 13 (a)”) has a concave curved surface on the surface opposite to the substrate. An object is to emit more light incident on the means 13 (a) to the substrate 11.

  Examples of the material of the diffusing unit 13 (a) include the materials exemplified for the substrate 11. Among these diffusing means 13 (a), glass and acrylic resin are preferable because they have a high light transmittance in the visible light wavelength region and excellent brightness of the surface light emitter.

The diffusing surface of the diffusing means 13 (a) may have one large concavo-convex surface over one diffusing means 13 (a), and one diffusing means 13 (a) has a plurality of small concavo-convex surfaces. May be.
The depth of the concave portion of the concave curved surface of the diffusing means 13 (a) is not particularly limited as long as it does not exceed the thickness of the diffusing means 13 (a), but more light is incident on the diffusing means 13 (a). It is preferable to be as deep as possible.

(Diffusion means 13 (b) having an uneven structure)
Diffusion means 13 (b) having a concavo-convex structure on the surface opposite to the substrate (hereinafter simply referred to as “diffusing means 13 (b)”) has a concavo-convex structure on the surface opposite to the substrate, thereby diffusing. An object is to emit more light incident on the means 13 (b) to the substrate 11.

  Examples of the diffusing means 13 (b) include a sheet having a known concavo-convex structure, and specific examples include a prism sheet; a cylindrical lens sheet; a microlens sheet.

Examples of the prism sheet include known prism sheets, and specifically, a sheet having a triangular cross section and a columnar concave structure as shown in FIG.
The shape, size, arrangement, filling rate, etc. of the lens can be appropriately set depending on the orientation distribution of the organic EL light emitting element 12, the ratio of the area where the organic EL light emitting element is in contact with the substrate and the area where the diffusion means is in contact with the substrate, etc. Good.

Examples of the cylindrical lens sheet include a known cylindrical lens sheet, and specifically include a sheet having a columnar convex structure with a hemispherical cross section as shown in FIG.
The shape, size, arrangement, filling rate, etc. of the lens can be appropriately set depending on the orientation distribution of the organic EL light emitting element 12, the ratio of the area where the organic EL light emitting element is in contact with the substrate and the area where the diffusion means is in contact with the substrate, etc. Good.

The microlens sheet is a sheet composed of a plurality of microlenses having a convex or concave structure such as a spherical shape, an elliptical spherical shape, a pyramid shape, or a conical shape.
Examples of the microlens sheet include known microlens sheets. Specifically, the microlens sheet has a hemispherical microlens sheet as shown in FIG. 6A and a quadrangular pyramid shape as shown in FIG. A microlens sheet etc. are mentioned.
The shape, size, arrangement, filling rate, etc. of the lens can be appropriately set depending on the orientation distribution of the organic EL light emitting element 12, the ratio of the area where the organic EL light emitting element is in contact with the substrate and the area where the diffusion means is in contact with the substrate, etc. Good.

  Examples of the material of the diffusing unit 13 (b) include the materials exemplified for the substrate 11. Among these diffusing means 13 (b), glass and acrylic resin are preferable because they have a high light transmittance in the visible light wavelength region and excellent brightness of the surface light emitter.

(Diffusion means 13 (c) made of resin containing fine particles)
The diffusing means 13 (c) made of resin containing fine particles (hereinafter simply referred to as “diffusing means 13 (c)”) diffuses light by the fine particles in the diffusing means 13 (c), and the diffusion means 13 (c) The purpose is to emit more light incident on the substrate 11 to the substrate 11.

  The material of the resin of the diffusing means 13 (c) is not particularly limited as long as it has a high light transmittance in the visible light wavelength region. For example, polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; Acrylic resin such as methyl methacrylate; Polycarbonate resin; Polyvinyl chloride resin; Styrenic resin such as polystyrene and ABS resin; Cellulose resin such as diacetyl cellulose and triacetyl cellulose; Polyolefin resin such as polyethylene and polypropylene; Polyimide resin; Aramid resin Etc. Among these resins, an acrylic resin is preferable because it has a high light transmittance in the visible light wavelength region and is excellent in luminance of the surface light emitter.

  The fine particles of the diffusing means 13 (c) are not particularly limited as long as they are fine particles having a light diffusing effect in the visible light wavelength region, and known fine particles can be used. The fine particles may be used alone or in combination of two or more.

  Examples of the fine particle material include gold, silver, silicon, aluminum, magnesium, zirconium, titanium, zinc, germanium, indium, tin, antimony, cerium, and other metals; silicon oxide, aluminum oxide, magnesium oxide, zirconium oxide, and oxide. Metal oxides such as titanium, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide, antimony oxide, and cerium oxide; metal hydroxides such as aluminum hydroxide; metal carbonates such as magnesium carbonate; silicon nitride Metal nitrides such as acrylic resin, styrene resin, silicone resin, urethane resin, melamine resin, epoxy resin and the like. These fine particle materials may be used alone or in combination of two or more. Among these fine particle materials, silicon, aluminum, magnesium, silicon oxide, aluminum oxide, magnesium oxide, aluminum hydroxide, magnesium carbonate, acrylic resin, because of excellent handling properties when forming the diffusion means 13 (c) Styrene resin, silicone resin, urethane resin, melamine resin, and epoxy resin are preferable, and silicon oxide, aluminum oxide, aluminum hydroxide, magnesium carbonate, acrylic resin, styrene resin, silicone resin, urethane resin, melamine resin, and epoxy resin particles are used. More preferred are acrylic resins and silicone resins, and silicone resins are particularly preferred.

  The volume average particle diameter of the fine particles is preferably 0.5 to 20 μm, more preferably 1.0 to 15 μm, and still more preferably 1.5 to 10 μm because light in the visible wavelength region can be effectively scattered.

  Examples of the shape of the fine particles include a spherical shape, a cylindrical shape, a cubic shape, a rectangular parallelepiped shape, a pyramid shape, a conical shape, a star shape, and an indefinite shape. These fine particles may be used singly or in combination of two or more. Among these fine particle shapes, a spherical shape, a cubic shape, a rectangular parallelepiped shape, a pyramid shape, and a star shape are preferable, and a spherical shape is more preferable because light in the visible wavelength range can be effectively scattered.

  The content of the resin and fine particles in the diffusing means 13 (c) is preferably 50 to 99% by mass of resin and 1 to 50% by mass of fine particles, and 60 to 97% by mass of resin and 3 to 40% of fine particles in the total amount of diffusing means 13. More preferably, the resin is 70 to 95% by mass, and more preferably 5 to 30% by mass of fine particles. When the resin and fine particle content of the diffusing means 13 (c) is 50% by mass or more and 50% by mass or less of the fine particles, the handling property at the time of forming the diffusing means 13 (c) is excellent. When the resin and fine particle content of the diffusing means 13 (c) is 99% by mass or less of the resin and 1% by mass or more of the fine particles, light in the visible wavelength region can be effectively scattered, and the luminance of the surface light emitter can be increased. Excellent.

  The refractive index difference between the resin and the fine particles in the diffusing means 13 (c) is preferably 0.02 or more because it can effectively scatter light in the visible wavelength region and is excellent in the luminance of the surface light emitter. 0.04 or more is more preferable.

The diffusion means 13 may be a diffusion means combining the diffusion means 13 (a) and the diffusion means 13 (c), or a diffusion means combining the diffusion means 13 (b) and the diffusion means 13 (c).
Since the diffusing unit 13 can emit more light incident on the diffusing unit 13 (a) to the substrate 11, a reflecting layer may be provided on the surface opposite to the substrate. Examples of the reflective layer include a layer made of a known material having light reflectivity.

The diffusing means 13 may contain other components as long as the effects of the present invention are not impaired. Examples of the other components include various additives such as a release agent, an antistatic agent, a leveling agent, an antifouling property improver, a dispersion stabilizer, and a viscosity modifier.
The content of other components in the diffusing means 13 is preferably 30% by mass or less, preferably 20% by mass or less, because it can effectively scatter light in the visible wavelength region and is excellent in the luminance of the surface light emitter. More preferred is 10% by mass or less.

The method for forming the diffusion means 13 is not particularly limited, but since the process is simple, the diffusion means 13 is stacked on the substrate 11 in the gap between the organic EL light emitting elements 12 after the organic EL light emitting elements 12 are stacked on the substrate 11. Is preferred.
Examples of the lamination method of the diffusing means 13 include a method of directly attaching the diffusing means 13, a method of applying the diffusing means 13 dissolved and dispersed in a solvent and drying the solvent, and applying a curable composition of the diffusing means 13. And a method of curing with ultraviolet rays or heat. The shape imparting such as the concave curved surface of the diffusing means 13 (a) and the concavo-convex structure of the diffusing means 13 (b) may be formed at the time of lamination using a mold or the like.

The ratio of the area where the organic EL light emitting element 12 is in contact with the substrate 11 and the area where the diffusion means 13 is in contact with the substrate 11 is preferably 50:50 to 99: 1, and preferably 60:40 to 98: 2. More preferably, it is more preferably 70:30 to 97: 3.
When the area where the organic EL light-emitting element 12 is in contact with the substrate 11 is equal to or greater than the lower limit and the area where the diffusion means 13 is in contact with the substrate 11 is equal to or less than the upper limit, the seams of the organic EL light-emitting elements 12 are reduced. Excellent. In addition, when the area where the organic EL light emitting element 12 is in contact with the substrate 11 is equal to or less than the upper limit value and the area where the diffusion means 13 is in contact with the substrate 11 is equal to or greater than the lower limit value, it is easy to form the diffusion means 13 and manufacture the surface light emitter. Cheap.

(Light extraction layer 14)
A light extraction layer 14 is preferably disposed on the light emitting surface side of the substrate 11 in order to improve the luminance of the surface light emitter and make the luminance of the surface light emitter more uniform.
Examples of the light extraction layer 14 include known organic EL light extraction members. Specifically, a sheet having an uneven structure such as a prism sheet, a cylindrical lens sheet, and a microlens sheet; a coating layer made of fine particles, and the like. .

Examples of the prism sheet, the cylindrical lens sheet, and the microlens sheet include the sheet exemplified as the diffusion means 13 (b) described above.
The shape, size, arrangement, filling rate, etc. of the lens can be appropriately set depending on the orientation distribution of the organic EL light emitting element 12, the ratio of the area where the organic EL light emitting element is in contact with the substrate and the area where the diffusion means is in contact with the substrate, etc. Good.

The light extraction layer 14 may include fine particles as necessary in order to make the luminance of the surface light emitter more uniform.
Examples of the fine particles include the fine particles exemplified as the fine particles of the diffusion means 13 (c) made of the resin containing the fine particles described above. The volume average particle diameter of the preferred fine particles and the preferred fine particle shape are also the same as those of the diffusion means 13 (c) made of the resin containing the fine particles.

Examples of the coating layer with fine particles include a coating layer with known fine particles.
Examples of the method for forming a coating layer with fine particles include a method of dispersing in a dispersion medium, applying the fine particles and drying the dispersion medium, and a method of applying a curable composition containing the fine particles and curing with ultraviolet light, heat, or the like. It is done.

(Method for manufacturing surface light emitter 10)
In the method for manufacturing the surface light emitter 10 according to the present invention, a plurality of organic EL light emitting elements 12 are disposed on the light incident surface side of the substrate 11 and the diffusion means 13 is provided in the gap between the organic EL light emitting elements 12. The order to do is not specifically limited.
As a method for manufacturing the surface light emitter 10 of the present invention, for example, an adhesive layer 15 is laminated on the light incident surface side of the substrate 11, a plurality of organic EL light emitting elements 12 are disposed on the adhesive layer 15, and organic EL light emission is performed. There is a method in which the diffusing means 13 is disposed in the gap between the elements 12 and, if necessary, the light extraction layer 14 is laminated on the light emitting surface side of the substrate 11 via the adhesive layer 15.

  The substrate 11 may have a member such as a hook for fixing the organic EL light emitting element 12. By using such a member, when the organic EL light emitting element 12 is deteriorated, the organic EL light emitting element 12 can be replaced.

(Use of surface light emitter 10)
The surface light emitter of the present invention can emit light uniformly over the entire surface light emitter and can have a large area. Therefore, the surface light emitter can be suitably used for, for example, illumination, a display, a screen, etc. Illumination is particularly preferable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.

As the surface light emitter, one in which the light extraction layer 14, the adhesive layer 15, the substrate 11, the adhesive layer 15, and the organic EL light emitting element 12 were laminated in this order and the diffusion means 13 was disposed in the gap between the organic EL light emitting elements 12 was used. Each layer of the surface light emitter was optically adhered.
The light extraction layer 14 is a film (refractive index: 1.49, thickness: 45 μm) containing 30% by mass of fine particles (refractive index: 1.42, diameter: 2.0 μm) with a convex spherical shape (diameter: 50 μm, height: 25 μm). , Hexagonal arrangement, filling rate 90%). The dimension of the light extraction layer 14 was 110 mm × 330 mm.
The adhesive layer 15 used had a refractive index of 1.49 and a thickness of 20 μm. In addition, the dimension of the adhesion layer 15 was 110 mm x 330 mm.
As the substrate 11, an acrylic resin plate having a refractive index of 1.49 and a thickness of 2 mm was used. The dimension of the substrate 11 was 110 mm × 330 mm.
As the organic EL light emitting element 12, a layer in which an organic EL light emitting element substrate 21, a light emitting layer 23, and a second electrode 24 are laminated in this order from the light emitting surface side was used. In addition, each layer of the organic EL light emitting element 12 was optically adhered, and the dimension of the organic EL light emitting element 12 was 100 mm × 100 mm.
As the organic EL light emitting element substrate 21, a glass plate having a refractive index of 1.51 and a thickness of 0.7 mm was used.
The light emitting layer 23 was 1 μm.
The second electrode 24 having a thickness of 1 mm was used, and the reflectance of the surface in contact with the light emitting layer 23 was set to 90%.
As the diffusing means 13, the one described in Examples described later was used. The size of the diffusing means was 10 mm × 100 mm, and was placed in the gap between the organic EL light emitting elements 12.

  The light was emitted from the light emitting layer 23 and emitted through each layer of the surface light emitter, and the amount of light emitted from the light extraction layer 14 was calculated by a light receiver (dimension 150 mm × 400 mm). The distribution of light emitted from the light emitting layer 23 was set to Lambertian distribution, the amount of light was set to 1 W, the number of light beams was set to 100 million, and the amount of emitted light was calculated.

  In the examples and comparative examples, the amount of light emitted is simulated by using light tracing software LightTools (Optical Research Associates), and the portion of the organic EL light emitting element of the surface light emitter and the joint of the organic EL light emitting element are determined. Calculated and compared.

[Example 1]
As the diffusing means 13, a rectangular pyramid (vertical angle 90 degrees, pitch 100 μm, height 50 μm) arranged in a rectangular array in a layer having a refractive index of 1.49 and a thickness of 0.7 mm so as to be closely packed in a rectangular array Was used to calculate the amount of emitted light.

[Example 2]
As the diffusing means 13, a concave structure square pyramid (vertical angle 90 degrees, pitch 100 μm, depth 50 μm) is arranged in a layer having a refractive index of 1.49 and a thickness of 0.7 mm so as to be closely packed in a rectangular arrangement, Furthermore, the amount of emitted light was calculated using a reflection layer provided on the surface opposite to the substrate.

[Example 3]
As the diffusing means 13, a layer having a refractive index of 1.49 and a thickness of 0.7 mm containing 5% by mass of fine particles (refractive index of 1.42, diameter of 2.0 μm) was used, and the amount of emitted light was calculated.

[Example 4]
As the diffusing means 13, a layer having a refractive index of 1.49 and a thickness of 0.7 mm containing 20% by mass of fine particles (refractive index of 1.42, diameter of 2.0 μm) was used, and the amount of emitted light was calculated.

[Comparative Example 1]
The amount of light emitted from the surface light emitter without the diffusing means 13 was calculated.

[Comparative Example 2]
Instead of the diffusing means 13, a flat layer having a refractive index of 1.49 and a thickness of 0.7 mm was used, and the amount of emitted light was calculated.

  Table 1 shows the results of Examples 1 to 4 and Comparative Examples 1 and 2.

In addition, the kind of spreading | diffusion means in Table 1 represents the following.
A: Diffusion means having a concavo-convex structure on the surface opposite to the substrate B: Diffusion means made of resin containing fine particles C: Flat layer not diffusing Further, the visibility in Table 1 represents the following criteria.
○: The light emission at the joint of the organic EL light emitting element was improved Δ: The light emission at the joint of the organic EL light emitting element was slightly improved ×: The light emission at the joint of the organic EL light emitting element was not improved

  From Table 1, compared with the surface light emitters of Comparative Examples 1 and 2 that did not provide the diffusing means, the surface light emitters of Examples 1 to 4 that provided the diffusing means were connected to the joints of the organic EL light emitting elements. It was found that the luminescence was improved.

  The surface light emitter of the present invention can emit light uniformly over the entire surface light emitter and can have a large area, and thus can be suitably used for lighting, displays, screens, and the like.

DESCRIPTION OF SYMBOLS 10 Surface light emitter 11 Substrate 12 Organic EL light emitting element 13 Diffusion means 14 Light extraction layer 15 Adhesive layer 21 Organic EL light emitting element substrate 22 1st electrode 23 Light emitting layer 24 2nd electrode

Claims (5)

A plurality of organic EL light emitting elements are arranged on the light incident surface side of the substrate, and a surface light emitter having a diffusing means in a gap between the organic EL light emitting elements,
A surface light emitter in which the diffusing means is a diffusing means having a concave curved surface on the surface opposite to the substrate, or a diffusing means having a concavo-convex structure on the surface opposite to the substrate. The surface opposite to the substrate of the diffusion means further comprises a reflective layer, the surface-emitting body according to claim 1. The surface light emitter according to claim 1 or 2 , wherein a ratio of an area where the organic EL light emitting element is in contact with the substrate and an area where the diffusing unit is in contact with the substrate is 50:50 to 99: 1. Furthermore, the light extraction layer is disposed on the light emitting surface side of the substrate, the surface-emitting body according to any one of claims 1 to 3 claim 1. The surface light emitter according to claim 4 , wherein the light extraction layer is a microlens sheet.