JP2014220036A - Organic electroluminescence device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a top emission type organic EL device which prevents great changes in colors or brightness regardless of viewing angles and can suppress the cost of manufacturing.SOLUTION: An organic EL device 1 has a top emission type organic EL element 2 and a connection board disposed on the organic EL element 2. The organic EL element 2 has a first electrode layer 221, an organic layer 222 disposed on the first electrode layer 221, and a second electrode layer 223 disposed on the organic layer 222; and both electrode layers 221, 223 have terminals 221a, 223a, respectively. The connection board 3 has a base film 31 and a conductive part 32 partially disposed within a plane of the base film 31. The conductive part 32 of the connection board 3 is electrically connected to the terminals 221a, 223a. The base film 31 has a light-diffusing function and covers a light-emission region 23 of the organic EL element 2.

Description

  The present invention relates to an organic electroluminescence device.

In general, an organic electroluminescence element has a structure in which an organic electroluminescence layer is stacked on an element substrate. The organic electroluminescence layer has at least a first electrode layer having a first terminal, an organic layer, and a second electrode layer having a second terminal. When electricity is passed through the organic electroluminescence element, the light emitting layer included in the organic layer emits light. In recent years, application of such an organic electroluminescence element to a lighting device or the like has been studied. Hereinafter, “organic electroluminescence” is simply referred to as “organic EL”.
In general, an organic EL element from which light is extracted from the upper side of the element substrate (the side on which the organic EL layer is laminated) is called a top emission type organic EL element, and the organic EL element from which light is extracted from the lower side of the element substrate Is called a bottom emission type organic EL element.

As described above, the organic EL element has a structure in which a plurality of layers are stacked on an element substrate. In such a structure, the phase of light (emitted light) emitted from the light emitting layer is likely to change due to multiple interference at the interface of each layer. When the phase of the emitted light changes, there is a problem that the color and luminance of the organic EL element change depending on the direction (viewing angle) in which the organic EL element is observed.
In order to solve such a problem, it is conventionally known to laminate a light diffusion film on an organic EL element (for example, Patent Document 1). By laminating the light diffusing film, the light extraction efficiency of the organic EL element is improved, and as a result, an organic EL element in which color and luminance do not change greatly depending on the viewing angle can be obtained.

By the way, it is conventionally known to use a flexible printed circuit board (FPC) as an electric supply means for the organic EL element (for example, Patent Document 2). The FPC is a connection substrate in which a conductive part is provided on a base film having flexibility and insulation. An organic EL device is formed by electrically connecting the FPC and the organic EL element.
Generally, a polyimide film is used as a base film for FPC. Since polyimide is a colored synthetic resin, when electricity is supplied to the top emission type organic EL device using FPC, the base film should not overlap the light emitting region (the region above the light emitting layer) of the organic EL device. A designed FPC is required. This is because when an FPC base film (polyimide film) is present in the light emitting region, not only the organic EL element looks tinted, but also the color and brightness of the emitted light vary greatly depending on the viewing angle due to multiple interference.
However, since the planar shape of the organic EL element is various, the shape of the base film of the FPC needs to be individually designed so as to avoid a light emitting region in accordance with the connected organic EL element. Therefore, the manufacturing cost of FPC is high, and as a result, there is a problem that the manufacturing cost of the organic EL element with FPC (organic EL device) increases.

JP 2009-70814 A JP 2007-258053 A

  An object of the present invention is to provide a top emission type organic EL device in which the color and luminance do not change greatly depending on the viewing angle, and the manufacturing cost can be suppressed.

  The organic EL device of the present invention includes a top emission type organic EL element and a connection substrate provided on the organic EL element, and the organic EL element includes a first electrode layer and the first electrode. An organic layer provided on the layer, and a second electrode layer provided on the organic layer, both electrode layers each having a terminal extending outside the organic layer, The connection substrate has a base film and a conductive portion partially provided in the plane of the base film, and the conductive portion and the terminal of the connection substrate are electrically connected, The base film has a light diffusing function and covers the light emitting region of the organic EL element.

  In the preferable organic EL device of the present invention, a plurality of the organic EL elements are arranged in parallel in a tile shape to form a light emitting panel, and the base film includes a plurality of the organic EL elements included in the light emitting panel. It covers all light emitting areas of the EL element.

  According to the present invention, since the base film of the connection substrate has a light diffusing function, it is possible to prevent the color and brightness of the emitted light emitted from the organic EL element from greatly changing depending on the viewing angle. Moreover, since the connection board used by this invention is designed so that a base film may cover the light emission area | region of an organic EL element, manufacturing cost is low compared with the connection board | substrate designed so that a light emission area | region may be avoided. Therefore, the organic EL device of the present invention can reduce the manufacturing cost.

The schematic plan view which shows one Embodiment of the organic EL element used by this invention. The expanded sectional view which cut | disconnected the organic EL element of FIG. 1 by the II-II line. The schematic rear view which shows one Embodiment of the connection board used by this invention. The center part abbreviation enlarged sectional view which cut the connection substrate of Drawing 3 with the IV-IV line. FIG. 4 is a schematic plan view showing an organic EL device obtained by connecting the organic EL element of FIG. 1 and the connection substrate of FIG. 3. The expanded sectional view which cut | disconnected the organic EL device of FIG. 5 by the VI-VI line. The schematic plan view which shows the some organic EL element (light emission panel) used by the modification of this invention. The schematic rear view which shows the connection board | substrate used by the modification of this invention. The schematic plan view which shows the organic EL device which concerns on the modification of this invention obtained by connecting the light emission panel of FIG. 7, and the connection board | substrate of FIG. The expanded sectional view which cut | disconnected the organic EL device of FIG. 9 by XX.

  The present invention will be described below with reference to the drawings. However, it should be noted that dimensions such as layer thickness and length in each figure are different from actual ones. Also, in this specification, there are cases where first, second, etc. are added as prefixes of terms, but these prefixes are added only for distinguishing terms, such as order and superiority. It has no special meaning. Further, in this specification, “upper” meaning a direction refers to the upper side of the drawing on the basis of an organic EL device placed on a horizontal plane as shown in FIG. 6, and “lower” denotes the lower side of the drawing. Point to.

[Configuration of organic EL device]
The organic EL device of the present invention includes an organic EL element and a connection substrate provided on the organic EL element so as to cover the light emitting region.
The organic EL element has a first electrode layer, an organic layer provided on the first electrode layer, and a second electrode layer provided on the organic layer. Furthermore, both electrode layers each have a terminal extending outside the organic layer.
The connection substrate includes a base film and a conductive portion partially provided in the plane of the base film.
The conductive portion of the connection board and the terminal are electrically connected. By connecting the conductive portion of the connection substrate to an external power source, electricity is supplied from the external power source to the organic EL element via the conductive portion.

In this specification, for the sake of convenience, it is assumed that the first electrode layer of the organic EL device is an anode layer and the second electrode layer is a cathode layer. However, in the organic EL device of the present invention, the first electrode layer may be a cathode layer and the second electrode layer may be an anode layer.
Hereinafter, the organic EL element used in the organic EL device of the present invention and the configuration of the connection substrate will be described separately, and then the organic EL device of the present invention will be described.

<Organic EL device>
FIG. 1 is a schematic plan view showing an embodiment of an organic EL element 2 used in the present invention, and FIG. 2 is an enlarged sectional view of the same.
The organic EL element 2 includes an element substrate 21 and an organic EL layer 22 provided on the element substrate 21. The organic EL layer 22 includes at least a first electrode layer 221 provided on the element substrate 21, an organic layer 222 provided on the first electrode layer 221, and a second electrode layer provided on the organic layer 222. 223.
Both electrode layers 221 and 223 have terminals 221a and 223a, respectively. Specifically, a part of the first electrode layer 221 that extends outside the organic layer 222 (one end side in the width direction of the element substrate 21) is the first terminal 221a. A part of the second electrode layer 223 that extends outside the organic layer 222 (the other end in the width direction of the element substrate 21) is a second terminal 223a. Both terminals 221 a and 223 a are portions for electrically connecting the organic EL element 2 and an external power source via the connection substrate 3. That is, both terminals 221a and 223a are parts for receiving and receiving electricity from an external power source.
The organic EL element 2 used in the present invention is a top emission type organic EL element 2. The top emission type organic EL element 2 can extract light from the upper side of the element substrate 21.

In the present invention, the layer structure of the organic EL element 2 is not particularly limited as long as the above conditions are satisfied, and an arbitrary layer can be added.
For example, as shown in FIG. 2, the organic EL element 2 of the present invention may be provided with a sealing layer 224 on the second conductive layer 223. The sealing layer 224 is, for example, a layer that covers the organic EL layer 22 without a gap except for the first terminal 221a and the second terminal 223a. Since the sealing layer 224 has moisture resistance, the organic layer 222 can be prevented from coming into contact with moisture.

As described above, the first electrode layer 221 is an anode layer, and the second electrode layer 223 is a cathode layer. In this case, the first terminal 221a is an anode terminal, and the second terminal 223a is a cathode terminal.
Hereinafter, in this specification, the first electrode layer 221 is represented as the anode layer 221, the second electrode layer 223 is represented as the cathode layer 223, the first terminal 221a is represented as the anode terminal 221a, and the second terminal 223a is represented as the cathode terminal 223a. It expresses.

The organic layer 222 of the organic EL element 2 in FIGS. 1 and 2 has three functional layers. That is, the organic layer 222 includes a hole transport layer 222a, a light emitting layer 222b, and an electron transport layer 222c in order from the bottom.
The hole transport layer 222a has a function of injecting holes into the light emitting layer 222b, and the electron transport layer 222c has a function of injecting electrons into the light emitting layer 222b.
When electricity flows through the anode layer 221 and the cathode layer 223, electrons and holes injected into the light-emitting layer 222b are recombined to generate excitons. When the exciton returns to the ground state, the light emitting layer 222b emits light.

  However, the layer structure of the organic layer is not limited to the three-layer structure as described above, (A) a structure composed of two layers, a hole transport layer and a light-emitting layer, (B) a light-emitting layer and an electron transport layer, A structure composed of two layers may be employed. In the organic layer (A), the light emitting layer also serves as the electron transport layer. In the organic layer (B), the light emitting layer also serves as the hole transport layer.

The planar view shape of the organic EL element used in the present invention is not particularly limited, but generally an organic EL element having a substantially rectangular shape in plan view is used, and preferably an organic band having a substantially strip shape in plan view as shown in FIG. An EL element 2 is used.
If an organic EL element having a substantially band shape in plan view is used, a large organic EL device can be obtained by arranging a plurality of organic EL elements in parallel in the width direction. The details of the large organic EL device will be described later as a modification of the present invention.
The size of the organic EL element having a substantially band shape in plan view is not particularly limited, but generally the width: length of the organic EL element is 1: 3 to 1:20, preferably 1: 4 to 1: 10.

The arrangement of the anode terminal and the cathode terminal of the organic EL element used in the present invention is not particularly limited. However, when the above-described organic EL element having a substantially band shape in plan view is used, preferably, an anode terminal and a cathode terminal are provided at both ends in the width direction of the organic EL element.
In FIG. 1, an anode terminal 221 a is provided at one end in the width direction of the organic EL element 2, and a cathode terminal 223 a is provided at the other end in the width direction of the organic EL element 2. Both terminals 221a and 223a are provided so as to extend in a strip shape from one end in the length direction of the organic EL element 2 to the other end in the length direction.

The organic EL element 2 has a light emitting region 23. The light emitting region 23 is a region above the light emitting layer 222b. Specifically, the light emitting region 23 is the surface of the uppermost member or part of the organic EL element 2 and corresponds to the light emitting layer 222b. That is, the light emitting layer 222 b exists below the light emitting region 23. In FIG. 1, for the sake of convenience, the light emitting region 23 is shown with a lattice pattern.
The organic EL element 2 in FIGS. 1 and 2 is provided with a sealing layer 224 on the top thereof. Therefore, the light emitting region 23 is substantially the entire upper surface of the sealing layer 224. Most of the light emitted from the light emitting layer 222 b is emitted from the light emitting region 23 to the outside of the organic EL element 2.

The organic EL element 2 used in the present invention is a top emission type. Therefore, the member and / or part above the light emitting layer 222b is preferably transparent, and more preferably colorless and transparent. That is, in the organic EL element 2 of FIGS. 1 and 2, the hole transport layer 222c, the cathode layer 223, and the sealing layer 224 are preferably transparent.
In this specification, “transparent” means that the total light transmittance is 70% or more, and “colorless” means that the yellowness (yellowness index) is 40 or less. The total light transmittance can be measured according to JIS K7375, and the yellowness can be measured according to JIS K 7103.

  Hereinafter, materials for forming each member and part (element substrate, anode layer, organic layer, cathode layer, sealing layer) of the organic EL element will be described in detail.

The element substrate is a plate-like member on which organic EL layers are stacked.
The element substrate is not particularly limited, and examples thereof include a glass plate, a ceramic plate, a synthetic resin film, and a metal thin plate. The element substrate may be either transparent or opaque.
Moreover, in order to prevent the temperature rise of the organic EL element at the time of driving, the element substrate is preferably excellent in heat dissipation, and has moisture resistance in order to prevent moisture from entering the organic EL layer. Is preferred.
Considering such heat resistance and moisture resistance, it is preferable to use a metal thin plate as the element substrate. In addition, when using a metal thin plate, in order to prevent a short circuit with the anode layer formed in the surface, the insulating layer may be provided in the upper surface of the metal thin plate.

An organic EL layer is a laminated body provided on an element substrate, and has an anode layer, an organic layer, and a cathode layer.
The anode layer is made of a conductive film.
The material for forming the anode layer is not particularly limited. For example, indium tin oxide (ITO); indium tin oxide containing silicon oxide (ITSO); aluminum; gold; platinum; nickel; tungsten; copper; Can be mentioned. Although the thickness of an anode layer is not specifically limited, Usually, it is 0.01 micrometer-1.0 micrometer.
As the method for forming the anode layer, an optimum method can be adopted depending on the forming material, and examples thereof include a sputtering method, a vapor deposition method, and an ink jet method. For example, when forming an anode with a metal, a vapor deposition method is used.

The organic layer has a structure composed of three layers: a hole transport layer, a light emitting layer, and an electron transport layer.
The hole transport layer is provided on the anode layer. The hole transport layer is a layer having a function of injecting holes into the light emitting layer.
The material for forming the hole transport layer is not particularly limited as long as the material has a hole transport function. As a material for forming the hole transport layer, an aromatic amine compound such as 4,4 ′, 4 ″ -tris (carbazol-9-yl) -triphenylamine (abbreviation: TcTa); 1,3-bis (N— Carbazole derivatives such as carbazolyl) benzene; spiro such as N, N′-bis (naphthalen-1-yl) -N, N′-bis (phenyl) -9,9′-spirobisfluorene (abbreviation: Spiro-NPB) Examples of the material for forming the hole transport layer may be one kind or a combination of two or more kinds, and the hole transport layer has a multilayer structure of two or more layers. There may be.
Although the thickness of a positive hole transport layer is not specifically limited, From a viewpoint of reducing the drive voltage of an organic EL device, 1 nm-500 nm are preferable.
Further, as a method for forming the hole transport layer, an optimum method can be adopted depending on the forming material, and examples thereof include a sputtering method, a vapor deposition method, an ink jet method, and a coating method.

The light emitting layer is provided on the hole transport layer.
The material for forming the light emitting layer is not particularly limited as long as it is a light emitting material. As a material for forming the light emitting layer, for example, a low molecular light emitting material such as a low molecular fluorescent light emitting material or a low molecular phosphorescent light emitting material can be used.
Examples of such a low-molecular light-emitting material include aromatic dimethylidene compounds such as 4,4′-bis (2,2′-diphenylvinyl) -biphenyl (abbreviation: DPVBi); 5-methyl-2- [2- Oxadiazole compounds such as [4- (5-methyl-2-benzoxazolyl) phenyl] vinyl] benzoxazole; 3- (4-biphenylyl) -4-phenyl-5-t-butylphenyl-1, Triazole derivatives such as 2,4-triazole; styrylbenzene compounds such as 1,4-bis (2-methylstyryl) benzene; benzoquinone derivatives; naphthoquinone derivatives; anthraquinone derivatives; fluorenone derivatives; azomethine zinc complexes, tris (8-quinolinolato) And organometallic complexes such as aluminum (Alq ₃ ).
Although the thickness of a light emitting layer is not specifically limited, For example, 2 nm-500 nm are preferable.
In addition, as a method for forming the light emitting layer, an optimum method can be adopted depending on the forming material, but it is usually formed by vapor deposition.

The electron transport layer is provided on the light emitting layer. The electron transport layer has a function of injecting electrons into the light emitting layer.
The material for forming the electron transport layer is not particularly limited as long as the material has an electron transport function. Examples of the material for forming the electron transport layer include tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), bis (2-methyl-8-quinolinolato) (4-phenylphenolato) aluminum (abbreviation: BAlq), and the like. Metal complex; 2,7-bis [2- (2,2′-bipyridin-6-yl) -1,3,4-oxadiazo-5-yl] -9,9-dimethylfluorene (abbreviation: Bpy-FOXD) 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (p-tert-butylphenyl) ) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 2,2 ′, 2 ″-(1,3,5-phenylene) -tris (1-phenyl- 1H-benzimidazole (Abbreviation: TPBi) heteroaromatic compounds, such as poly (2,5-pyridine - diyl) (abbreviation: PPy) polymer compounds, such as and the like. The material for forming the electron transport layer may be used alone or in combination of two or more. The electron transport layer may have a multilayer structure of two or more layers.
Although the thickness of an electron carrying layer is not specifically limited, From a viewpoint of reducing the drive voltage of an organic EL device, and a viewpoint of raising the transparency of an electron carrying layer, 1 nm-500 nm are preferable.
The electron transport layer is preferably transparent, and more preferably colorless and transparent. Such an electron transport layer can be formed by appropriately changing the material and thickness of the electron transport layer.
As the method for forming the electron transport layer, an optimum method can be adopted depending on the forming material, and examples thereof include a sputtering method, a vapor deposition method, an ink jet method, and a coating method.

The cathode layer is made of a conductive film.
The material for forming the cathode layer is not particularly limited. As a material for forming a conductive cathode layer, indium tin oxide (ITO); indium tin oxide containing silicon oxide (ITSO); zinc oxide to which a conductive metal such as aluminum is added (ZnO: Al); magnesium -Silver alloy etc. are mentioned. Although the thickness of a cathode layer is not specifically limited, Usually, they are 0.01 micrometer-1.0 micrometer.
The cathode layer is preferably transparent, more preferably colorless and transparent. Such a cathode layer can be formed by appropriately changing the material and thickness of the cathode layer.
As a method for forming the cathode layer, an optimum method can be adopted depending on the forming material, and examples thereof include a sputtering method, a vapor deposition method, and an ink jet method. For example, when the cathode layer is formed of ITO, a sputtering method is used, and when the cathode layer is formed of a magnesium-silver alloy or a magnesium-silver laminated film, an evaporation method is used.

The sealing layer is a moisture-proof layer provided on the cathode layer.
The material for forming the sealing layer is not particularly limited as long as it has moisture resistance. Examples of the material for forming the sealing plate include ethylene tetrafluoroethyl copolymer (ETFE), high density polyethylene (HDPE), stretched polypropylene (OPP), polystyrene (PS), polymethyl methacrylate (PMMA), stretched nylon ( ONy), synthetic resins such as polyethylene terephthalate (PET), polycarbonate (PC), polyimide, polyether styrene (PES), polyethylene naphthalate (PEN); silicon nitride (SiN), silicon carbide (SiC), silicon carbide oxide ( A nitride containing Si, such as SiOC) or nitrided silicon carbide oxide (SiOCN), can be preferably used.
Moreover, it is preferable that the said sealing layer has flexibility. As a material for forming a flexible sealing layer, it is conceivable to use glass or metal.
The thickness of the sealing layer is not particularly limited, and is 0.2 μm to 50 μm, preferably 0.2 μm to 10 μm, and more preferably 0.2 μm to 2 μm.
The sealing layer is preferably transparent and more preferably colorless and transparent. Such a sealing layer can be formed by appropriately changing the forming material and thickness of the sealing layer.
The sealing layer may have a single layer structure or a multilayer structure including other layers. Although the formation method of a sealing layer is not specifically limited, For example, when a sealing layer is a single layer, a sealing layer is formed by a vapor deposition method, More preferably, it forms by a plasma assist vapor deposition method.

When the sealing layer has a multilayer structure, the sealing layer may include an adhesive layer laminated on the cathode layer and a sealing plate laminated on the adhesive layer (having a two-layer structure). preferable.
The forming material of the sealing plate is not particularly limited, and examples thereof include a film using a synthetic resin, which is the above-described forming material of the sealing layer, and a glass plate.
The material for forming the adhesive layer is not particularly limited. For example, the adhesive layer is formed using a conventionally known adhesive. As the adhesive, for example, a thermosetting adhesive or a photocurable adhesive can be used. Examples of the thermosetting adhesive include an adhesive mainly composed of an epoxy resin, a phenol resin, a polyurethane resin, or a melamine resin. As the photocurable adhesive, typically, an ultraviolet curable adhesive can be used.

Further, when the sealing layer has a multilayer structure, the sealing layer includes a protective film laminated on the cathode layer, an adhesive layer laminated on the protective film, and a sealing laminated on the adhesive layer. And a plate (having a three-layer structure).
The protective film is a film having a function of preventing the organic EL element from being damaged and a function of preventing intrusion of moisture, oxygen, and the like.
The material for forming the protective film is not particularly limited. Examples of the material for forming the protective film include metals and metalloids, preferably oxides, oxynitrides, nitrides, and oxycarbonitrides thereof. Examples of the metal or metalloid oxide include MgO, SiO, Si _x O _y (X> 0, Y> 0), Al ₂ O ₃ , GeO, and Ti ₂ O.
Preferably, the material for forming the protective film is a semimetal oxynitride, nitride, or oxycarbonitride, and more preferably, silicon oxide carbide (SiOC), silicon oxynitride (SiON), or silicon nitride (SiN). At least one selected from the group consisting of:

<Connecting board>
3 and 4 show an example of the connection substrate 3 used in the present invention. FIG. 3 is a schematic rear view showing an embodiment of the connection substrate 3 used in the present invention, and FIG. 4 is an enlarged cross-sectional view omitting the central portion.
The connection substrate 3 is a member that supplies electricity from the external power source to the organic EL element 2. The connection substrate 3 includes a base film 31 and a conductive portion 32 partially provided in the plane of the base film 31. The conductive part 32 has conductivity, and the base film 31 does not have conductivity.
The conductive portion 32 is a portion that electrically connects the organic EL element 2 and an external power source, and the base film 31 is a member on which the conductive portion 32 is disposed. The conductive part 32 has at least an anode terminal connection part 321 and a cathode terminal connection part 322.
The anode terminal connection part 321 is a part connected to the anode terminal 221 a of the organic EL element 2, and the cathode terminal connection part 322 is a part connected to the cathode terminal 223 a of the organic EL element 2.

In the plane of the base film 31, the arrangement of the conductive portions 32 is not particularly limited, and the emission region of the organic EL element 2, the arrangement of the anode terminal 221 a and the cathode terminal 223 a of the organic EL element 2 to which the connection substrate 3 is connected, The base film 31 can be appropriately changed in consideration of the planar view shape.
The connection substrate 3 in FIG. 3 is connected to, for example, an organic EL element 2 having a substantially band shape in plan view as shown in FIG. Therefore, the connection substrate 3 is designed according to the arrangement of the anode terminal 221a and the cathode terminal 223a of the organic EL element 2.

Specifically, the base film 31 of the connection substrate 3 shown in FIG. 3 is slightly larger than the planar view shape of the organic EL element 2 (element substrate 21) and substantially the same shape as the planar view shape of the organic EL element 2 ( (Substantially belt-like).
The conductive portion 32 includes a strip-like anode terminal connecting portion 321 extending substantially parallel to the longitudinal direction at one end portion in the width direction of the base film 31 (right end portion in FIG. 3), and the other end portion in the width direction of the base film 31 ( A strip-shaped cathode terminal connecting portion 322 extending substantially parallel to the longitudinal direction is provided at the left end portion in FIG.
Further, the conductive portion 32 is connected to the anode of the external power source and has a substantially rectangular external power source first connection portion 323a in plan view, and a first midway portion 324a that connects the external power source first connection portion 323a and the anode terminal connection portion 321. And having. The conductive portion 32 is connected to the cathode of the external power source 4 and has a substantially rectangular external power source second connection portion 323b in plan view, and a second midway portion connecting the external power source second connection portion 323b and the cathode terminal connection portion 322. 324b.
The anode terminal connection part 321, the first intermediate part 324a, and the external power supply first connection part 323a are formed in a continuous line shape, and the cathode terminal connection part 322, the second intermediate part 324b, and the external power supply second connection. The part 323b is also formed in a continuous linear shape.
Electricity flowing from the external power supply is supplied to both connection parts 321 and 322 via both external power supply connection parts 323a and 323b and both intermediate parts 324a and 324b.

The proportion of the conductive portion in the plane of the base film is not particularly limited. However, as described later, when the conductive portion overlaps the light emitting region of the organic EL element, the light extraction efficiency of the organic EL device may be reduced. Therefore, it is desirable that the area occupied by the conductive portion is small in the plane of the base film.
Moreover, the connection board | substrate may have parts other than an electroconductive part (not shown).

The material for forming the conductive portion is not particularly limited as long as it is a conductive member, and any material can be used. Examples of such a forming material include metals such as aluminum, platinum, gold, silver, copper, copper alloys, nickel, cobalt, and titanium; metal oxides such as ITO and zinc oxide; inorganic materials such as graphite; It is done. Since the electrical resistance is low, the material for forming the conductive portion is preferably copper.
As will be described later, the conductive portion preferably does not overlap the light emitting region of the organic EL element, but when the conductive portion overlaps the light emitting region, the conductive portion is preferably transparent, more preferably colorless and transparent. . As a material for forming the transparent conductive portion, a metal oxide such as zinc oxide is preferably used.

The method of forming the conductive portion in the plane of the base film is not particularly limited. For example, a method of bonding a conductive wire (conductive portion) containing a conductive portion forming material on the base film with an adhesive, formation of the conductive portion A method of partially forming a circuit-like thin film (conductive part) containing material on the surface of the base film by plating, sputtering or vapor deposition, and laminating the thin film containing the material for forming the conductive part on the entire surface of the base film Then, a method of forming the thin film into a circuit shape, and the like can be mentioned.
Preferably, the conductive portion can be obtained by laminating a thin film containing a material for forming the conductive portion over the entire surface of the base film, and then forming the thin film in a circuit shape.
The method for laminating the thin films is not particularly limited, and for example, an adhesive, plating, sputtering, or vapor deposition can be employed. Moreover, the method of forming the thin film in a circuit shape is not particularly limited, and for example, etching can be employed.
Specifically, for example, a circuit pattern is formed by printing an etching resist in a circuit shape on the surface of a thin film laminated on the entire surface of the base film, and the portion where the circuit pattern is not formed using an etching solution. The conductive portion is formed by a method of removing the thin film and then removing the etching resist.

The base film has a light diffusing function. That is, the base film is a light diffusion film. The base film diffuses outgoing light emitted from the light emitting layer of the organic EL element.
The base film is not particularly limited as long as it has mechanical strength necessary for providing the conductive portion, and has an insulating property and a light diffusion function, and a conventionally known light diffusion film can be used. . The base film is preferably colorless and transparent. When the base film is colorless and transparent, its total light transmittance is 70% or more, and its yellowness (yellowness index) is 40 or less.

Hereinafter, an example of the base film 31 will be described with reference to FIG. In FIG. 4, two alternate long and short dash lines mean that illustration of the base film 31 between the two lines is omitted.
As shown in FIG. 4, the base film 31 includes a matrix resin 311 and light diffusing fine particles 312 dispersed in the matrix resin 311. The matrix resin 311 and the light diffusing fine particles 312 have different refractive indexes. Therefore, the emitted light emitted from the light emitting layer of the organic EL element is diffused inside the base film 31, and the light extraction efficiency of the organic EL element can be improved.
The refractive index difference between the light diffusing fine particles 312 and the matrix resin 311 is not particularly limited, but is generally 0.02 or more, and preferably 0.05 or more. If the refractive index difference between the two is less than 0.02, a sufficient light scattering effect may not be obtained.

The matrix resin and the light diffusing fine particles which are constituent members of the base film may be colorless and transparent, or may be colored and opaque.
However, the base film is preferably colorless and transparent. Therefore, the matrix resin that is a main member occupying most of the base film is preferably colorless and transparent, and more preferably the matrix resin and the light diffusing fine particles are colorless and transparent.

The kind of light diffusing fine particles is not particularly limited, and may be organic fine particles or inorganic fine particles. As the organic fine particles, polymethyl methacrylate beads, acrylic-styrene copolymer beads, melamine beads, polycarbonate beads, styrene beads, crosslinked polystyrene beads, polyvinyl chloride beads, benzoguanamine-melamine formaldehyde beads and the like are used. Further, as the inorganic fine particles, SiO ₂ (for example, amorphous silica-based beads), ZrO ₂ , TiO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , etc. are used.
The number average particle diameter of the light diffusing fine particles is not particularly limited, but is preferably 0.1 μm to 2.0 μm, more preferably 0.5 μm to 1.0 μm.

  The matrix resin is not particularly limited, and examples thereof include ethylene-vinyl acetate copolymer (EVA), polyester, polypropylene (PP), polyethylene resin, polyamide resin, and ethylene-ethyl acrylate copolymer resin (EEA). .

Moreover, the compounding quantity of the light-diffusion fine particle with respect to 100 mass parts of matrix resins is although it does not specifically limit, Usually, 10 mass parts-50 mass parts, Preferably, they are 10 mass parts-35 mass parts.
When the blending amount of the light diffusing fine particles is less than 10 parts by mass, the light diffusion effect of the base film may be reduced. When the blending amount of the light diffusing fine particles is more than 50 parts by mass, the transparency of the base film may be lowered. There is.

  In the connection substrate of the present invention, since the base film has a light diffusion function, the light extraction efficiency of the organic EL element can be improved, and as a result, the organic EL device in which the color and luminance do not vary greatly depending on the viewing angle. Can be formed. In addition, the connection substrate of the present invention does not need to design a base film so as to avoid the light emitting region, and thus the manufacturing cost can be suppressed. Furthermore, in the present invention, since the connection substrate has both the power supply function and the light diffusion function for the organic EL element, the thickness of the organic EL device can be further reduced.

<Organic EL device>
By electrically connecting the connection substrate 3 to the organic EL element 2, the organic EL device 1 of the present invention is formed. FIG. 5 is a schematic plan view showing an embodiment of the organic EL device 1 of the present invention, and FIG. 6 is an enlarged cross-sectional view thereof.
In FIG. 5, the organic EL element 2 is represented by a broken line for convenience, and the conductive portion 32 of the connection substrate 3 is represented by a one-dot chain line for convenience (the same applies to FIG. 9).
The organic EL device 1 of FIG. 5 is formed by connecting the anode terminal 221a and the cathode terminal 223a of the organic EL element 2 and the conductive portion 32 (the anode terminal connection portion 321 and the cathode terminal connection portion 322) of the connection substrate 3. Yes.
Further, the conductive portion 32 is further connected to the external power source 4, and electricity flowing from the external power source 4 is supplied to the organic EL element 2.

As shown in FIG. 5, the base film 31 of the connection substrate 3 is slightly larger than the element substrate 21 of the organic EL element 2 and has substantially the same shape (substantially strip shape). The base film 31 is connected so as to cover the entire upper side of the organic EL element 2. However, in the present invention, it is not necessary for the entire upper side of the organic EL element 2 to be covered with the base film 31, and at least the light emitting region 23 of the organic EL element 2 only needs to be covered with the base film 31.
By covering the light emitting region 23 with the base film 31, most of the emitted light emitted from the light emitting layer 222 b passes through the inside of the base film 31. The light that has passed through the base film 31 is diffused by the light diffusion effect of the base film 31, so that the light extraction efficiency of the organic EL device 1 can be improved, and as a result, the color and brightness vary greatly depending on the viewing angle. The organic EL device 1 that is not used can be formed.

In FIG. 5, the conductive portion 32 provided in the plane of the base film 31 of the connection substrate 3 does not overlap the light emitting region 23. This is because if the conductive portion 32 overlaps the light emitting region 23, the light extraction efficiency of the organic EL device 1 may be reduced.
However, when a transparent material (for example, high-purity zinc oxide) is used as the material for forming the conductive portion 32, a part of the conductive portion 32 may overlap the light emitting region 23.

  In addition, a gap may exist between the lower surface of the base film 31 of the connection substrate 3 and the light emitting region 23 of the organic EL element 2, but preferably the lower surface of the base film 31 as shown in FIG. 6. 311 and the light emission area | region 23 are contact | abutting, More preferably, the lower surface 311 of the base film 31 and the light emission area | region 23 are bonded together through the adhesive layer (not shown). In FIG. 6, the light emitting region 23 is substantially the entire upper surface of the sealing layer 224.

The connection method between the connection substrate 3 and the organic EL element 2 is not particularly limited, and any connection method can be adopted as long as both the connection portions 321 and 322 and both the terminals 221a and 223a can be energized.
Preferably, as shown in FIG. 6, both terminal connecting portions 321 and 322 and both terminals 221 a and 223 a are connected by a conductive adhesive layer 5.
Such a conductive adhesive layer 5 can be formed using, for example, an anisotropic conductive film (ACF).
The thickness of the conductive adhesive layer 5 is not particularly limited, but is generally 10 μm to 50 μm.

In the organic EL device of the present invention, the light emitting region of the organic EL element is covered with the base film of the connection substrate. The base film has a light diffusion function and can improve the light extraction efficiency of the organic EL device. Therefore, in the organic EL device of the present invention, the color and luminance do not change greatly depending on the viewing angle. Moreover, in this invention, since it is not necessary to design a base film so that a base film may avoid a light emission area | region, the manufacturing cost of a connection board can be held down, As a result, the manufacturing cost of an organic EL device can be held down. .
Further, in the present invention, the connection substrate has both a function of diffusing light emitted from the organic EL element and a function of supplying electricity to the organic EL element. Therefore, the organic EL device can be formed thinner.

  Hereinafter, modifications of the present invention will be described. However, in the description of the following modified examples, configurations and effects different from those of the above-described embodiment will be mainly described, and descriptions of the same configurations and the like as those of the above-described embodiments may be omitted, and terms and symbols may be used.

<Modification>
In the organic EL device 1 according to the above embodiment, one connection substrate 3 is connected to one organic EL element 2, but the present invention is not limited to this embodiment, and a plurality of organic EL elements 2 are connected. One connection board 3 may be connected to the above.
FIG. 7 is a schematic plan view showing a plurality of organic EL elements 2 (light emitting panels 7) used in the organic EL device 1 according to this modification, and FIG. 8 shows the connection substrate 3 used in this modification. FIG. 9 is a schematic plan view, FIG. 9 is a schematic plan view of an organic EL device 1 according to this modification, and FIG. 10 is an enlarged cross-sectional view of the organic EL device 1 of FIG.
The organic EL device 1 shown in FIGS. 9 and 10 is formed by electrically connecting the connection substrate 3 shown in FIG. 8 and the plurality of organic EL elements 2 (light-emitting panels 7) shown in FIG.

As shown in FIG. 7, in this modification, the light emitting panel 7 is formed by arranging a plurality of organic EL elements 2 in a tile shape. In addition, the structure of each organic EL element 2 shown in FIG. 7 is the same as that of the organic EL element 2 which concerns on embodiment mentioned above. In FIG. 7, the plurality of organic EL elements 2 are arranged in parallel on the base material 6 and fixed to the base material 6.
Note that “the organic EL elements are arranged in parallel in a tile shape” means that the light emitting regions of the organic EL elements are arranged so as not to overlap each other. The organic EL elements are preferably arranged at a necessary interval. All the intervals between the organic EL elements may be constant or different. However, it is preferable that the organic EL elements are arranged at regular intervals.
Although the space | interval between each organic EL element is not specifically limited, Usually, it is 0.1 mm-0.5 mm, Preferably, it is 0.1 mm-0.3 mm.

FIG. 8 shows the connection substrate 3 attached to the plurality of organic EL elements 2 (light emitting panel 7) arranged in parallel. In FIG. 8, the conductive part 32 provided in the surface of the base film 31 of the connection substrate 3 includes an anode terminal connection part 321, a cathode terminal connection part 322, both external power supply connection parts 323a and 323b, and both middle parts 324a, 324b, and a plurality of (three in this modification) connector portions 323 provided intermittently between the anode terminal connection portion 321 and the cathode terminal connection portion 322.
The connector portion 323 is a portion that is electrically connected so as to straddle the cathode terminal 223 a of one organic EL element 2 adjacent in the light emitting panel 7 and the anode terminal 221 a of the other organic EL element 2.

The planar view shape of the connector part is not particularly limited, but is preferably a planar view band shape. In the case of a band in plan view, adjacent anode terminals and cathode terminals can be connected even if there is a slight misalignment when connecting the connection substrate and the plurality of organic EL elements (light emitting panels).
The connector part is formed of a conductive material. The connector part may be formed from a lump of conductive material fixed in the base film surface, for example. Examples of the material for forming the connector portion include the same materials as the anode terminal connection portion and the cathode terminal connection portion described above.

9 and 10 show an organic EL device 1 according to a modification of the present invention. This organic EL device 1 connects the anode terminal 221a of the organic EL element 2 located at one end (left end in FIG. 7) of the light-emitting panel 7 shown in FIG. 7 and the anode terminal connection portion 321 of the connection substrate 3 shown in FIG. The cathode terminal 223a of the organic EL element 2 located at the other end (right end in FIG. 7) of the light emitting panel 7 is connected to the cathode terminal connecting portion 322 of the connection substrate 3, and the organic EL element adjacent in the light emitting panel 7 is connected. Two anode terminals 221 a and two cathode terminals 223 a are connected via a connector portion 323. That is, in the organic EL device 1 according to this modification, a plurality of organic EL elements 2 are electrically connected by the connection substrate 3 and are structurally integrated.
In addition, the connection method of the connector part 323 and both terminal 221a, 223a is not specifically limited, The method similar to the connection method of the anode terminal connection part 321 and the cathode terminal connection part 322 is employable. Preferably, the connector portion 323 and both terminals 221 a and 223 a are connected by the conductive adhesive layer 5.

  In this modification, the connector part is provided in the plane of the base film of the connection board, but the present invention is not limited to this embodiment, and the connector part is independent of the connection board. It may be a separate member. In such a case, after connecting the anode and cathode terminals of the organic EL elements adjacent in the light-emitting panel to each other through the connector part which is a separate member, the anode terminal connection part and the cathode terminal connection are made in the plane of the base film. An organic EL device can be formed by connecting a connection substrate having a portion to a light-emitting panel.

In the organic EL device according to this modification, all the light emitting regions of the plurality of organic EL elements included in the light emitting panel are covered with the base film of the connection substrate. Therefore, the emitted light emitted from the light emitting regions of all the organic ELs included in the light emitting panel can be effectively diffused.
Moreover, in this modification, since the organic EL device has a plurality of organic EL elements, a large organic EL device can be formed.

  The organic EL device of the present invention can be used as a display device or a lighting device.

  DESCRIPTION OF SYMBOLS 1 ... Organic EL device, 2 ... Organic EL element, 21 ... Element substrate, 22 ... Organic EL layer, 221 ... 1st electrode layer (anode layer), 221a ... 1st terminal (anode terminal), 222 ... Organic layer, 223 2nd electrode layer (cathode layer), 223a ... 2nd terminal (cathode terminal), 23 ... light emitting region, 3 ... connection substrate, 31 ... base film, 321 ... anode terminal connection part, 322 ... cathode terminal connection part, 323 ... Connector part, 4 ... External power supply, 5 ... Conductive adhesive layer, 6 ... Base material, 7 ... Light emitting panel

Claims (2)

A top emission type organic electroluminescence element;
A connection substrate provided on the organic electroluminescence element,
The organic electroluminescence element has a first electrode layer, an organic layer provided on the first electrode layer, and a second electrode layer provided on the organic layer,
Both electrode layers each have a terminal extending outside the organic layer,
The connection substrate has a base film, and a conductive portion partially provided in the plane of the base film,
The conductive portion of the connection board and the terminal are electrically connected,
The said base film has a light-diffusion function, and has covered the light emission area | region of the said organic electroluminescent element, The organic electroluminescent device characterized by the above-mentioned. A light emitting panel is formed by arranging a plurality of the organic electroluminescence elements in a tile shape in parallel.
The organic electroluminescent device according to claim 1, wherein the base film covers all the light emitting regions of the plurality of organic electroluminescent elements included in the light emitting panel.

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