JP5895762B2 - Organic electroluminescent device and organic electroluminescent panel sealing method - Google Patents

Description

  The present invention relates to a sealing method of an organic electroluminescence element applicable to uses such as a display device and a lighting device, and a sealing method of an organic electroluminescence panel manufactured by arranging a plurality of the organic electroluminescence elements.

  Organic electroluminescence devices (organic EL devices) using organic materials are considered promising for use in, for example, solid light-emitting inexpensive large-area full-color display devices and light-emitting devices for writing light source arrays. Is being actively promoted.

  The organic EL element generally includes a substrate, a first electrode, an organic compound layer including a light emitting layer, and a second electrode, and the first electrode, the organic compound layer, and the second electrode are formed on the substrate in this order. Element. Here, one of the first electrode and the second electrode constitutes an anode, and the other constitutes a cathode. The light emitting layer is composed of one or a plurality of organic layers containing an organic light emitting substance.

  In the organic EL element having such a configuration, when a voltage is applied between the first electrode and the second electrode, holes are injected from the one electrode (anode) into the light emitting layer and light is emitted from the other electrode (cathode). Electrons are injected into the layer. Then, when holes and electrons injected into the light emitting layer recombine in the light emitting layer, the energy level of the organic light emitting material returns from the conduction band to the valence band, and the energy generated at this time is converted into light from the light emitting layer. Released.

By the way, in recent years, in the technical field of organic EL elements, light weight, flexibility, easy handling, and the like have been demanded in particular due to demands for curved surface installation and enlargement of organic EL elements.
The flexible organic EL element is characterized in that it can be installed on a curved surface. For example, an element that has been sealed in a flat shape can be used at the time of subsequent curved surface installation depending on the characteristics of the resin used. Sealing performance such as peeling of the sealing end may be deteriorated due to tension or the like due to bending of the organic EL element.
In addition, when the organic EL element is sealed in a bent state, the tension due to the bending is relieved. However, especially when a large panel is used, handling and setting in a bent state are handled. There is a problem in terms of.
Therefore, in the organic EL element which has flexibility, development of the sealing technique for hold | maintaining favorable sealing performance (light emission performance) after installing in a curved surface is desired.

Conventionally, in order to seal an organic EL element, an operation of pasting an organic EL element and a sealing substrate through an adhesive is performed, and pasting is performed in a planar manner by vacuum lamination or roll lamination. Thereafter, curing by heating or curing by ultraviolet irradiation is generally performed.
In this case, there is a merit that the organic EL element can obtain the original curing degree and sealing ability by one operation, but the organic EL element once cured as described above is bent for installation, etc. When the deformation is performed, the sealed end portion may be easily peeled off over a long period of time due to tension due to bending.

  As another sealing method, there has been proposed a sealing technique in which heating is performed for a certain period of time at a first curing temperature as a stepwise temperature-curing, and then the temperature is increased and further processing is performed for a certain period of time (see Patent Document 1). However, this is a stepwise temperature increase in order to relieve stress due to rapid heating, and does not match the intention of the present invention.

JP 2007-134321 A

  Accordingly, the main object of the present invention is a method for sealing an organic EL element capable of maintaining good sealing performance (light emission performance) when installed on a curved surface, and a plurality of organic electroluminescent elements arranged in an array. It is providing the sealing method of an organic electroluminescent panel.

  The said subject is achieved by the following structure.

1. On the flexible element substrate, an organic electrolayer having a pair of electrodes, an organic compound layer having at least one light emitting layer between the electrodes, and further having an adhesive layer and a flexible sealing substrate. A method for sealing a luminescence element,
A primary curing step of curing the adhesive layer;
A step of curving said organic electroluminescence element,
A secondary curing step of curing the adhesive layer in a state where the organic electroluminescence element is curved ;
A method for sealing an organic electroluminescent element, comprising:
2. In the sealing method of the organic electroluminescent element according to the above 1,
In the primary curing step, the reaction rate of the constituent material of the adhesive layer is 5 to 30%,
In the secondary curing step, the reaction rate of the constituent material of the adhesive layer is set to 70% or more.

3 . In the sealing method of the organic electroluminescent element according to 1 or 2 ,
The constituent material of the said adhesive bond layer is a thermosetting adhesive or an ultraviolet curable adhesive, The sealing method of the organic electroluminescent element characterized by the above-mentioned.

4 . In the sealing method of the organic electroluminescent element as described in any one of 1 to 3 ,
A sealing method of an organic electroluminescence element, wherein after the primary curing step, the organic electroluminescence element is sealed and packaged and then opened before being bent .

5 . In the sealing method of the organic electroluminescent element according to any one of 1 to 4 ,
Sealing method of an organic electroluminescent device characterized by disposing an adhesive layer comprising a pressure sensitive adhesive on the side portion of the adhesive layer.

6 . On the flexible element substrate, an organic electrolayer having a pair of electrodes, an organic compound layer having at least one light emitting layer between the electrodes, and further having an adhesive layer and a flexible sealing substrate. A method for sealing an organic electroluminescence panel in which a plurality of luminescence elements are arranged,
A primary curing step of curing the adhesive layer;
Forming a plurality of organic electroluminescence elements to form an organic electroluminescence panel; and
A step of bending the organic electroluminescence panel,
A secondary curing step of curing the adhesive layer in a state where the organic electroluminescence panel is curved ;
A method for sealing an organic electroluminescence panel, comprising:

  ADVANTAGE OF THE INVENTION According to this invention, the sealing method of the organic EL element which can hold | maintain favorable sealing performance (light emission performance) when it installs on a curved surface, and the organic electroluminescent panel produced by arranging in multiple numbers of this organic electroluminescent element The sealing method can be provided.

It is sectional drawing which shows schematic structure of an organic EL element. It is sectional drawing which shows schematic structure of the organic EL element which has a pressure sensitive adhesive layer. It is a schematic diagram which shows schematic structure of a continuous vacuum film-forming apparatus. It is a schematic diagram which shows schematic structure of the continuous body of an organic EL element. It is sectional drawing which shows schematic structure of an organic electroluminescent panel. It is a top view which shows schematic structure of the organic electroluminescent panel by a serial connection system. It is a figure which shows the electrical connection of the organic electroluminescent panel by a serial connection system, Comprising: (a) is a top view, (b) has shown sectional drawing. It is a top view which shows schematic structure of the organic electroluminescent panel by an individual electric power feeding system. It is a figure which shows the electrical connection of the organic electroluminescent panel by an individual electric power feeding system, Comprising: (a) is a top view, (b) has shown sectional drawing. It is sectional drawing which shows schematic structure of the organic electroluminescent panel which coat | covered the electrode connection part with protective resin. It is sectional drawing which shows schematic structure of the organic electroluminescent panel which coat | covered the electrode connection part with the protection base material.

  First, before describing the configuration of the organic EL element of the present embodiment, the problems to be solved by the present invention will be described more specifically.

In the present invention, when the organic EL element is produced, the effect of the present invention can be obtained by dividing the curing of the sealing adhesive layer into a primary curing step and a secondary curing step.
More specifically, first, initial deterioration due to moisture, oxygen, etc. of the element is suppressed in the primary curing step of the adhesive layer. Next, when the element is installed on the installation object, the element is deformed according to the shape (for example, a curved surface) of the installation object, and further, the adhesive layer is secondarily cured. As a result, it is possible to obtain an element that suppresses the risk of peeling off of the end portion of the element after sealing while suppressing initial element deterioration.
In particular, when the element is tiled to form a large panel, the fact that it can be bent at the time of installation is advantageous in terms of handling. The secondary curing step may be performed a plurality of times, and in this case, an element with higher sealing ability is obtained.

  Hereinafter, an example of an organic EL element according to an embodiment of the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the following example.

<< Configuration of organic EL element >>
[Overall configuration of organic EL element]
FIG. 1 shows a schematic cross-sectional view of an organic EL element according to an embodiment of the present invention.
As shown in FIG. 1, the organic EL element 1 is an element having flexibility, and includes an organic EL element main body 10, an adhesive layer 20, and a sealing substrate 30.
The organic EL element body 10 is bonded to the sealing substrate 30 via the adhesive layer 20. That is, the organic EL element 1 of the present embodiment is configured as a solid contact type element.

The organic EL element body 10 is configured by laminating an anode (first electrode) 12, an organic compound layer 13 including a light emitting layer, a cathode (second electrode) 14, and an inorganic film 15 in this order on an element substrate 11. Yes.
An inorganic insulating film 16 is formed between the anode 12 and the cathode 14 in a region near the outer peripheral end of the anode 12, that is, on a predetermined region in the non-light emitting region of the anode 12. In this embodiment, the insulating property between the anode 12 and the cathode 14 is secured by the inorganic insulating film 16 (electrical short circuit between the anode 12 and the cathode 14 is prevented).

  The cathode 14 is formed so as to cover the organic compound layer 13, and the inorganic film 15 is formed so as to cover the cathode 14. That is, the organic EL element 1 of the present embodiment has a configuration (three-layer sealing configuration) in which the organic compound layer 13 is sealed with three layers of the cathode 14, the inorganic film 15, and the adhesive layer 20. Therefore, in the organic EL element 1 of the present embodiment, sufficient sealing performance can be obtained even if the cathode 14, the inorganic film 15, and the adhesive layer 20 are thinned.

  In addition, by adopting such a sealing configuration, not only the upper surface (the surface on the sealing substrate 30 side) of the organic compound layer 13 but also the side surfaces are sealed by the cathode 14, the inorganic film 15, and the adhesive layer 20. Therefore, the seal width of the organic EL element 1 can also be narrowed (non-light emitting region can be reduced). That is, in the organic EL element 1 of the present embodiment, it is possible to suppress the change (deterioration) of the light emission quality with time without increasing the seal width and thickness (while ensuring flexibility).

  Although not shown in FIG. 1, the organic EL element body 10 is sealed with a sealing substrate 30 so that the external extraction electrode ends of the anode 12 and the cathode 14 are exposed to the outside.

  Further, in the organic EL element 1 of the present embodiment, the light emitted from the light emitting layer (organic compound layer 13) may be taken out only from the anode 12 side, or taken out from both the anode 12 and the cathode 14 sides. Alternatively, it may be taken out only from the cathode 14 side.

  In addition to the light emitting layer, the organic compound layer 13 includes various organic layers such as a carrier (hole and electron) injection layer, a blocking layer, and a transport layer, and is formed by laminating these various organic layers. May be. The configuration of each of these organic layers will be described in detail later.

  Hereinafter, the structure of each part and each layer of the organic EL element 1 will be described more specifically.

[Element substrate]
The element substrate 11 (base, substrate, base, support) can be formed of a transparent material such as glass or plastic, for example. In particular, the element substrate 11 is preferably composed of a glass substrate, a quartz substrate, or a flexible base material. As the flexible substrate, a transparent resin film, thin film glass, or the like can be used.

  Examples of the material for forming the transparent resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, and cellulose acetate propionate. (CAP), cellulose acetates such as cellulose acetate phthalate (TAC), cellulose nitrate, or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene , Polyetherketone, polyimide, polyethersulfone (PES), polyphenylenesulfur , Polysulfones, polyether imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic, polyarylates, Arton (registered trademark: manufactured by JSR) or Apel (registered trademark: manufactured by Mitsui Chemicals, Inc.) ) And the like.

When the element substrate 11 is composed of a transparent resin film, in order to suppress permeation of water vapor, oxygen and the like into the organic EL element 1, a film made of an inorganic material, a film made of an organic material, Or you may provide the hybrid film which laminated | stacked these films. In this case, the water vapor permeability (environmental condition: 25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) is about 0.01 g / [m ² · day · atm] or less. It is preferable to comprise the said film with a barrier film. In addition, the film has an oxygen permeability of about 10 ⁻³ cm ³ / [m ² · day · atm] or less and a water vapor permeability of about 10 ⁻³ g / [m ² · day · atm. It is more preferable to use a barrier film having the following values. Further, the film has an oxygen permeability of about 10 ⁻³ cm ³ / [m ² · day · atm] or less and a water vapor permeability of about 10 ⁻⁵ g / [m ² · day · atm. It is particularly preferable to use a barrier film having the following values.

  The “water vapor transmission rate” is a value measured by an infrared sensor method based on JIS (Japanese Industrial Standard) -K7129 (1992), and the “oxygen transmission rate” is JIS-K7126 (1987). It is a value measured by the coulometric method based on the year).

  As a material for forming the above-described barrier film (the coating film), any material can be used as long as it can suppress the intrusion of factors such as moisture and oxygen into the organic EL element 1 that cause deterioration of the organic EL element 1. Can be used. For example, the barrier film can be composed of a coating made of an inorganic material such as silicon oxide, silicon dioxide, or silicon nitride. In order to improve the brittleness of the barrier film, the barrier film is preferably composed of a hybrid film in which a film made of the inorganic material and a film made of an organic material are laminated. In this case, the order of laminating the film made of an inorganic material and the film made of an organic material is arbitrary, but it is preferable to laminate a plurality of both alternately.

  In addition, as a method for forming the barrier film as described above, any method can be used as long as the barrier film can be formed on the element substrate (transparent resin film) 11. For example, barrier film formation methods include vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma polymerization method (special Open 2004-68143), plasma CVD (Chemical Vapor Deposition) method, laser CVD method, thermal CVD method, coating method and the like.

[anode]
The anode 12 is an electrode film that supplies (injects) holes to the light-emitting layer, and has a large work function (4 eV or more). For example, the anode 12 is an electrode material such as a metal, an alloy, an electrically conductive compound, and a mixture thereof. It is formed.
Specifically, in the organic EL element 1, when light is extracted from the anode 12 side, the anode 12 is made of, for example, a metal such as Au, or a metal such as CuI, ITO (Indium Tin Oxide), SnO ₂ , or ZnO. It can be formed of a light transmissive electrode material such as a compound. In this case, the anode 12 can also be formed of an amorphous transparent electrode material such as IDIXO (registered trademark: In ₂ O ₃ —ZnO).

In the organic EL element 1, when light is extracted from the anode 12 side, the light transmittance of the anode 12 is preferably greater than about 10%. The sheet resistance (surface resistance) of the anode 12 is several hundred Ω / sq. The following values are preferred. Further, the film thickness of the anode 12 varies depending on the forming material, but is usually set to a value in the range of about 10 to 1000 nm, preferably about 10 to 200 nm.
On the other hand, in the organic EL element 1, when light is not extracted from the anode 12 side (when light is extracted only from the cathode 14 side), the anode 12 is made of a high reflectance such as a metal, an amorphous alloy, a microcrystalline alloy, or the like. It can also be formed of an electrode material having

  The anode 12 having the above configuration can be formed by a technique such as vapor deposition or sputtering, for example. At this time, the anode 12 may be formed in a desired shape pattern by using a photolithography technique. In the case where the accuracy of the shape pattern is not required in the anode 12 (when the accuracy is a value of about 100 μm or more), when the anode 12 is formed by a technique such as vapor deposition or sputtering, the desired shape is obtained. You may form the anode 12 of a desired pattern through the mask in which the pattern was formed.

[Organic compound layer]
As described above, the organic compound layer 13 includes various organic layers such as a light emitting layer, a carrier (hole and electron) injection layer, a blocking layer, and a transport layer.
Hereinafter, the configuration of each organic layer will be described.

(1) Hole Injection Layer In the organic EL device 1 of the present embodiment, a hole injection layer (anode buffer layer) is provided between the anode 12 and the light emitting layer or between the anode 12 and a hole transport layer described later. ) May be provided. The hole injection layer is a layer provided between the anode 12 and the light emitting layer or the hole transport layer in order to reduce the driving voltage of the organic EL element 1 and improve the light emission luminance.

  Here, a detailed description of the structure of the hole injection layer is omitted. For example, “Organic EL device and its forefront of industrialization” (published on November 30, 1998 by NTT) The structure of the hole injection layer is described in detail in Chapter 2, “Electrode Material” (pages 123-166). Moreover, as a forming material of a positive hole injection layer, the compound described in Unexamined-Japanese-Patent No. 2000-160328 can be used.

(2) Hole Transport Layer The hole transport layer is a layer that transports (injects) holes supplied from the anode 12 to the light emitting layer. The hole transport layer also acts as a barrier that prevents the inflow of electrons from the cathode 14 side. Therefore, the term hole transport layer is sometimes used in a broad sense and includes a hole injection layer and / or an electron blocking layer.

As a hole transport material, any material of an organic material and an inorganic material can be used as long as the material can exhibit the above-described effect of transporting (injecting) holes and blocking the inflow of electrons. it can.
Specifically, as a hole transport material, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styryl Anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers (especially thiophene oligomers), porphyrin compounds, aromatic tertiary amine compounds (styrylamine compounds), etc. Compounds.

  Aromatic tertiary amine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -[1,1'-biphenyl] -4,4'-diamine (TPD), 2,2-bis (4-di-p-tolylaminophenyl) propane, 1,1-bis (4-di-p- Tolylaminophenyl) cyclohexane, N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl, 1,1-bis (4-di-p-tolylaminophenyl) -4-phenyl Cyclohexane, bis (4-dimethylamino-2-methylphenyl) phenylmethane, bis (4-di-p-tolylaminophenyl) phenylmethane, N, N'-diphenyl-N, N'-di (4-methoxyphenyl) ) -4, '-Diaminobiphenyl, N, N, N', N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis (diphenylamino) quadriphenyl, N, N, N-tri (p- Tolyl) amine, 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene, 4-N, N-diphenylamino- (2-diphenylvinyl) benzene, 3- A styrylamine compound such as methoxy-4'-N, N-diphenylaminostilbenzene, having two condensed aromatic rings in the molecule as described in US Pat. No. 5,061,569 For example, as described in 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD) and JP-A-4-308688. Examples include compounds such as 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) in which three triphenylamine units are linked in a starburst type. It is done.

  In addition, as the hole transport material, a polymer material in which the above-described various hole transport materials are introduced into a polymer chain, or a polymer material having the above-described various hole transport materials as a polymer main chain is used. You can also. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as a hole transport material and a material for forming a hole injection layer.

  Further, as a hole transport material, JP-A-11-251067, J. Org. Huang et. al. A material referred to as a so-called p-type hole transport material as described in literatures (Applied Physics Letters 80 (2002), p. 139) may be used. Note that when such a material is used as a hole transport material, a more efficient light-emitting element can be obtained.

  In this embodiment, the hole transport layer may be doped with an impurity to form a hole transport layer having a high p property (hole rich). Examples thereof include, for example, JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J.A. Appl. Phys. , 95, 5773 (2004). When such a hole-rich hole transport layer is used, the organic EL element 1 with lower power consumption can be produced.

  The hole transport layer can be formed by a technique such as spin coating or vapor deposition. Although the film thickness of a positive hole transport layer is suitably set according to conditions, such as a positive hole transport material to be used, Usually, about 5 nm-5 micrometers, Preferably it sets to the value within the range of about 5-200 nm. Note that only one hole transport layer may be provided or a plurality of layers may be provided. When the hole transport layer has a single layer structure, one or more materials among the above-described hole transport materials are included in the hole transport layer.

(3) Light-Emitting Layer The light-emitting layer is formed by directly injecting holes from the anode 12 or from the anode 12 through the hole transport layer and the like and directly from the cathode 14 or from the cathode 14 through the electron transport layer or the like. This layer emits light by recombination with the injected electrons. The light emitting portion may be inside the light emitting layer, or may be an interface between the light emitting layer and a layer adjacent thereto.

  Further, only one light emitting layer may be provided or a plurality of light emitting layers may be provided. When a plurality of light emitting layers are provided, a structure in which a plurality of light emitting layers having different emission colors are stacked may be used, or a non-light emitting intermediate layer may be provided between adjacent light emitting layers. The intermediate layer can be formed of the same material as the host compound described later in the light emitting layer.

In the present embodiment, the light emitting layer is formed of an organic light emitting material including a host compound (light emitting host) and a light emitting material (light emitting dopant). In the light emitting layer having such a configuration, an arbitrary emission color can be obtained by appropriately adjusting the emission wavelength of the light emitting material, the type of the light emitting material to be contained, and the like.
In addition, the light emitting layer can be formed using a technique such as a spin coating method or a vapor deposition method. The film thickness of the light emitting layer can be arbitrarily set. For example, the homogeneity of the constituent films, the prevention of unnecessary application of a high voltage during light emission, and the stabilization of the light emission color with respect to the drive current From the viewpoint of improving the properties, for example, it is preferably set to a value in the range of about 2 to 200 nm, and more preferably set to a value in the range of about 5 to 100 nm.

  Below, the structure of the host compound and luminescent material which are contained in a light emitting layer is demonstrated to a specific example.

(3-1) Host compound As the host compound contained in the light emitting layer, it is preferable to use a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C) of less than about 0.1. In particular, a compound having a phosphorescence quantum yield of less than about 0.01 is preferably used as the host compound. The volume ratio of the host compound in the light emitting layer is preferably about 50% or more among various compounds contained in the light emitting layer.

  A known host compound can be used as the host compound. At that time, one type of host compound may be used, or a plurality of types of host compounds may be used in combination. By using a plurality of types of host compounds, the mobility (movement amount) of electric charges (holes and / or electrons) can be adjusted, and the light emission efficiency of the organic EL element 1 can be improved.

  Examples of the host compound having the above-described characteristics include known low-molecular compounds, high-molecular compounds having repeating units, and low-molecular compounds having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light-emitting host). ) And the like can be used. As the host compound, it is preferable to use a compound having a hole transporting function, an electron transporting function, a function of preventing emission of longer wavelengths, and a high Tg (glass transition temperature).

  The “glass transition temperature (Tg)” is a value obtained by a method based on JIS-K7121 using a DSC (Differential Scanning Calorimetry) method.

  Specifically, as host compounds, JP-A Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786. Gazette, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645 No. 2002-338579, No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, same 002-231453, 2003-3165, 2002-234888, 2003-27048, 2002-255934, 2002-260861, 2002-280183, 2002 -29960 gazette, 2002-302516 gazette, 2002-305083 gazette, 2002-305084 gazette, 2002-308837 gazette, etc. The compound currently described in literatures is mentioned.

  In the present embodiment, the host compound is preferably a carbazole derivative, and particularly preferably a carbazole derivative and a dibenzofuran compound.

(3-2) Luminescent Material As the luminescent material (luminescent dopant), for example, a phosphorescent luminescent material (phosphorescent compound, phosphorescent luminescent compound), a fluorescent luminescent material (fluorescent luminescent material, fluorescent dopant) or the like is used. be able to. However, from the viewpoint of improving the light emission efficiency, it is preferable to use a phosphorescent light emitting material as the light emitting material.

A phosphorescent material is a compound that can emit light from an excited triplet. Specifically, the phosphorescent material is a compound that emits phosphorescence at room temperature (25 ° C.), and a phosphorescent quantum yield is a compound having a value of about 0.01 or more at 25 ° C. However, in the present embodiment, it is preferable to use a phosphorescent material having a phosphorescence quantum yield of about 0.1 or more.
The phosphorescence quantum yield can be measured, for example, by the method described on page 398 of "4th edition Experimental Chemistry Course 7 Spectroscopy II" (1992 edition, Maruzen). In addition, the phosphorescence quantum yield in the solution can be measured using various solvents, but in this embodiment, the phosphorescence emission material has a phosphorescence quantum yield of about 0.01 or more in any solvent. Any light emitting material can be used.

  Further, the light emitting layer may contain one kind of light emitting material, or may contain a plurality of kinds of light emitting materials having different light emission maximum wavelengths. By using a plurality of types of light emitting materials, it is possible to mix a plurality of lights having different emission wavelengths, thereby obtaining light of an arbitrary emission color. For example, white light can be obtained by including a blue dopant, a green dopant, and a red dopant (three kinds of light emitting materials) in the light emitting layer.

  As the process (principle) of light emission (phosphorescence emission) in the light emitting layer containing the host compound and the phosphorescent light emitting material described above, the following two kinds of processes can be mentioned.

The first light emission process is an energy transfer type light emission process. In this type of light emission process, first, carriers recombine on the host compound in the light emitting layer where carriers (holes and electrons) are transported, thereby generating an excited state of the host compound. The energy generated at this time moves from the host compound to the phosphorescent material (the energy level of the excited state moves from the excited level of the host compound to the excited level (excited triplet) of the luminescent material), As a result, light is emitted from the phosphorescent material.
The second light emission process is a carrier trap type light emission process. In this type of light emission process, a phosphorescent material traps carriers (holes and electrons) in the light emitting layer. As a result, carrier recombination occurs on the phosphorescent material, and light is emitted from the phosphorescent material.
In any of the light emission processes described above, the excited state energy level of the phosphorescent light emitting material needs to be lower than the excited state energy level of the light emitting host.

As the phosphorescent light emitting material that causes the above-described light emitting process, a desired phosphorescent light emitting material can be appropriately selected from various known phosphorescent light emitting materials used in conventional organic EL elements.
For example, as the phosphorescent material, a complex compound containing a metal element of Group 8 to Group 10 in the periodic table of elements can be used. Among such complex compounds, it is preferable to use any one of an iridium compound, an osmium compound, a platinum compound (platinum complex compound), and a rare earth complex as the phosphorescent material. In the present embodiment, it is particularly preferable to use an iridium compound as the phosphorescent material.

  Fluorescent materials include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes Examples thereof include dyes, polythiophene dyes, and rare earth complex phosphors.

In the present embodiment, the light emitted from the organic EL element 1 is measured with a spectral radiance meter (CS-1000, manufactured by Konica Minolta Sensing Co., Ltd.), and the measurement result is represented by CIE (International Commission on Illumination) chromaticity coordinates ( For example, the color of the light emitted from the organic EL element 1 when the color is applied to the “New Color Science Handbook” (see Figure 4.16 on page 108 of the Japan Color Society, edited by the University of Tokyo Press, 1985) To do. Specifically, the term “white” as used herein means that the chromaticity in the CIE 1931 color system at 1000 cd / m ² is X = 0.33 ± 0 when the 2-degree viewing angle front luminance is measured by the above method. .07, Y = 0.33 ± 0.07.

  In this embodiment, as a method for obtaining white light emission, a method in which a host compound contains a plurality of light emitting materials having different emission wavelengths is used, but the present invention is not limited to this. For example, a blue light emitting layer, a green light emitting layer, and a red light emitting layer may be laminated to form a light emitting layer, and light emitted from each color light emitting layer may be mixed to obtain white light emission.

(4) Electron Transport Layer The electron transport layer is a layer that transports (injects) electrons supplied from the cathode 14 to the light emitting layer. The electron transport layer also acts as a barrier that prevents holes from flowing in from the anode 12 side. Therefore, the term electron transport layer is sometimes used in a broad sense and includes an electron injection layer and / or a hole blocking layer.

  An electron transport layer adjacent to the cathode 14 side of the light emitting layer (when the electron transport layer has a single layer structure, the electron transport layer, and when a plurality of electron transport layers are provided, the electron transport layer positioned closest to the light emitting layer) As an electron transport material (also serving as a hole blocking material) used, any material can be used as long as it has a function of transmitting (transporting) electrons injected from the cathode 14 to the light emitting layer. For example, as the electron transporting material, an arbitrary material can be appropriately selected from known various compounds used in conventional organic EL elements.

  More specifically, as an electron transport material, a metal complex such as a fluorene derivative, a carbazole derivative, an azacarbazole derivative, an oxadiazole derivative, a trizole derivative, a silole derivative, a pyridine derivative, a pyrimidine derivative, and an 8-quinolinol derivative, a metal phthalocyanine or Examples thereof include metal-free phthalocyanines or compounds obtained by substituting their terminal groups with alkyl groups or sulfonic acid groups.

  In this embodiment, the electron transport layer may be doped with an impurity as a guest material to form an electron transport layer having a high n property (electron rich). Specific examples of the electron transport layer having such a structure are disclosed in, for example, JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. , 95, 5773 (2004). Specifically, an organic alkali metal salt can be used as the guest material (dope material).

When using an alkali metal salt of an organic substance as a doping material, the kind of the organic substance is arbitrary. For example, formate, acetate, propionate, butyrate, valerate, capronate, enanthate, caprylic acid Salt, oxalate, malonate, succinate, benzoate, phthalate, isophthalate, terephthalate, salicylate, pyruvate, lactate, malate, adipate, mesylate A compound such as a salt, a tosylate, and a benzenesulfonate can be used as the organic substance. Among these, especially formate, acetate, propionate, butyrate, valerate, caprate, enanthate, caprylate, oxalate, malonate, succinate or benzoate Is preferably used as an organic substance. More preferable organic substances are aliphatic carboxylic acids such as formate, acetate, propionate and butyrate. When this aliphatic carboxylic acid is used, the number of carbon atoms is preferably 4 or less. The most preferable compound as the organic substance is acetate.
Moreover, the kind of alkali metal which comprises the alkali metal salt of organic substance is arbitrary, For example, Li, Na, K, or Cs can be used. Among these alkali metals, a preferable alkali metal is K or Cs, and a more preferable alkali metal is Cs.

From the above, the alkali metal salt of the organic substance that can be used as the doping material for the electron transport layer is a compound that combines the organic substance and the alkali metal. Specifically, as a doping material, formic acid Li, formic acid K, formic acid Na, formic acid Cs, acetic acid Li, acetic acid K, Na acetate, acetic acid Cs, propionic acid Li, propionic acid Na, propionic acid K, propionic acid Cs, shu Acid Li, Na oxalate, oxalic acid K, oxalic acid Cs, malonic acid Li, malonic acid Na, malonic acid K, malonic acid Cs, succinic acid Li, succinic acid Na, succinic acid K, succinic acid Cs, benzoic acid Li , Na benzoate, benzoic acid K, or benzoic acid Cs. Among these, Li-acetate, K-acetate, Na-acetate or Cs-acetate is a preferred dope, and the most preferred dope is Cs-acetate.
In addition, preferable content of these dope materials is a value in the range of about 1.5-35 mass% with respect to the electron carrying layer to which a dope material is added, and more preferable content is about 3-25. The value is in the range of mass%, and the most preferable content is the value in the range of about 5 to 15 mass%.

The electron transport layer can be formed, for example, by a technique such as spin coating or vapor deposition. Moreover, although the film thickness of an electron carrying layer is suitably set according to conditions, such as an electron carrying material to be used, it is normally set to the value within the range of about 5 nm-5 micrometers, Preferably about 5-200 nm.
Note that only one electron transport layer or a plurality of electron transport layers may be provided. When the electron transport layer has a single-layer structure, one or more materials among the electron transport materials described above are included in the electron transport layer.

(5) Electron Injection Layer In the organic EL element 1 of the present embodiment, an electron injection layer (electron buffer layer) may be provided between the cathode 14 and the light emitting layer or between the cathode 14 and the electron transport layer. Good. Similar to the hole injection layer, the electron injection layer is a layer provided to reduce the driving voltage of the organic EL element 1 and to improve the light emission luminance.

  Here, detailed description of the structure of the electron injection layer is omitted, but for example, “Organic EL device and its industrialization front line” (issued by NTT, Inc., November 30, 1998) The structure of the electron injection layer is described in detail in the chapter “Electrode Material” (pages 123-166).

[cathode]
The cathode 14 is an electrode film that supplies (injects) electrons to the light emitting layer, and usually has a low work function (4 eV or less), such as a metal (electron-injecting metal), an alloy, an electrically conductive compound, and the like. It is formed with electrode materials, such as a mixture of these.
Specifically, in the organic EL element 1, when light is not extracted from the cathode 14, the cathode 14 is, for example, aluminum, sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver. It can be formed of a non-transparent electrode material such as a mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, an indium, a lithium / aluminum mixture, or a rare earth metal.
On the other hand, in the organic EL element 1, when light is extracted from the cathode 14 side, the cathode 14 can be formed of an electrode material having optical transparency. In the present embodiment, IDIXO (registered trademark: In ₂ O ₃ —ZnO), which is an amorphous transparent electrode material, is preferably used as a material for forming the cathode 14.
Moreover, the cathode 14 can be formed by techniques, such as vapor deposition and sputtering, for example.

[Inorganic film]
The inorganic film 15 (gas barrier layer) is provided in order to prevent water vapor from entering the organic compound layer 13 including the light emitting layer (for moisture prevention). The inorganic film 15 is preferably composed of a transparent inorganic film.
As the material for forming the inorganic film 15, any material can be used as long as it is an inorganic material that can prevent the organic EL element 1 from entering the organic EL element 1, which causes deterioration of the organic EL element 1. The inorganic film 15 is preferably composed of a film having a water vapor permeability of about 0.01 g / [m ² · day · atm] or less.

  Examples of the material for forming the inorganic film 15 having the above-described characteristics include inorganic materials such as silicon oxide, silicon dioxide, silicon nitride, and silicon oxynitride. In the present embodiment, in particular, the inorganic film 15 is preferably composed of a single film of silicon nitride or silicon oxynitride.

  In order to improve the fragility of the inorganic film 15, a film made of an organic material may be laminated on the inorganic film 15. In this case, the organic material includes a photo-curing sealant, a thermosetting sealant, a moisture-curing sealant such as 2-cyanoacrylate, and an epoxy-based heat and chemical-curing (two-component mixed) sealant. And a sealing agent such as a cationic curing type ultraviolet curable epoxy resin sealing agent.

  As a method for forming the inorganic film 15, any method can be used. For example, a vacuum deposition method, a sputtering method, a reactive sputtering method, a molecular beam epitaxy method, a cluster ion beam method, an ion plating method, a plasma weighting method, and the like. Examples thereof include a lawful method, an atmospheric pressure plasma polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, and a coating method.

In addition, when the film thickness of the inorganic film 15 is too thin, a defect etc. will generate | occur | produce in the inorganic film 15, and an adhesive agent will penetrate into the cathode 14 through this defect. In this case, due to the curing reaction of the adhesive layer 20, the cathode 14 is oxidized or the like, thereby causing an influence such as deterioration. Further, when the thickness of the cathode 14 is small, the adhesive enters the organic compound layer 13 through defects of the inorganic film 15 and the cathode 14, thereby causing an increase in dark spots.
On the other hand, when the film thickness of the inorganic film 15 is too thick, the productivity, flexibility, etc. of the organic EL element 1 are lowered. Further, the light emission performance may be deteriorated due to the influence of damage to the organic compound layer 13 and the like generated when the inorganic film 15 is formed.
Therefore, in this embodiment, the film thickness of the inorganic film 15 is appropriately set in consideration of these points. Specifically, the thickness of the inorganic film 15 is preferably set to a value less than about 1 μm, and particularly preferably set to a value in the range of about 100 to 250 nm.

[Inorganic insulating film]
The inorganic insulating film 16 is provided to prevent an electrical short circuit between the anode 12 and the cathode 14. The inorganic insulating film 16 is formed of an insulating film such as a SiO ₂ film, for example.
When the inorganic insulating film 16 is composed of a SiO ₂ film, it can be formed on the anode 12 by, for example, sputtering. The inorganic insulating film 16 can also be formed by forming a Si film on the anode 12 and then thermally oxidizing the Si film. Furthermore, the inorganic insulating film 16 can also be formed by a CVD method using a gas such as silane or tetraethoxysilane as a raw material gas under reduced pressure or normal pressure.

[Adhesive layer]
Examples of the adhesive used in the adhesive layer (sealing resin layer) 20 include a photocurable or thermosetting adhesive having a reactive vinyl group of an acrylic acid oligomer or a methacrylic acid oligomer, and a thermosetting resin such as an epoxy resin. Alternatively, chemical curable (two-component mixed) adhesives, hot melt type polyamides, polyesters, polyolefins, and cationic curable type ultraviolet curable epoxy resin adhesives may be mentioned.

  In this embodiment, it is preferable to form the adhesive layer 20 with a thermosetting adhesive from the viewpoint of simplicity of the manufacturing process. Moreover, as a form of the adhesive layer 20, it is preferable to use a thermosetting adhesive processed into a sheet shape. When a sheet-type thermosetting adhesive is used, it exhibits non-flowability at room temperature (about 25 ° C.) and exhibits fluidity at a temperature in the range of 50 to 120 ° C. when heated. An agent (sealant) is used.

  As the thermosetting adhesive, any adhesive can be used. In the present embodiment, a suitable thermosetting adhesive is appropriately selected from the viewpoint of improving the adhesiveness between the adhesive layer 20 and the adjacent sealing substrate 30, the element substrate 11, and the like. For example, as the thermosetting adhesive, it is possible to use a resin mainly composed of a compound having an ethylenic double bond at the end or side chain of a molecule and a thermal polymerization initiator. More specifically, a thermosetting adhesive made of an epoxy resin, an acrylic resin, or the like can be used. Moreover, according to the bonding apparatus and hardening processing apparatus which are used at the manufacturing process of the organic EL element 1, you may use a fusion type thermosetting adhesive.

  Moreover, what mixed 2 or more types of above-mentioned adhesives may be used as an adhesive agent, and the adhesive agent provided with both thermosetting and ultraviolet-curing property may be used.

  In addition, as shown in FIG. 2, an adhesive layer 22 made of a pressure-sensitive adhesive may be formed around the adhesive layer 20.

[Sealing substrate]
The sealing substrate 30 is configured by a film-like (plate-like) member, and is disposed to face the element substrate 11.
The sealing substrate 30 can be formed of a transparent material such as glass or plastic. In particular, it is preferable that the sealing substrate 30 is made of a glass substrate, a quartz substrate, or a flexible sealing member.

As the flexible sealing member, for example, a multilayer film member in which a resin layer and a barrier layer (a film made of an inorganic material) are laminated, or a member such as a thin film glass having flexibility can be used. A multilayer film member in which a resin layer and a barrier layer are laminated is used.
The thickness of the flexible sealing member is preferably set to a value in the range of about 10 to 300 μm in consideration of characteristics such as handling at the time of manufacture, tensile strength, and stress cracking resistance of the barrier layer. .
In addition, "thickness" here is an average thickness of a flexible sealing member, for example, using a micrometer, respectively along the vertical direction and the width direction of a flexible sealing member. It is an average value of thicknesses measured at about 10 locations.

Moreover, when the sealing base material 30 is comprised with a flexible sealing member, the water content of the flexible sealing member at the time of sealing is the organic compound layer 13 which generate | occur | produces with the carrying-in water | moisture content of a flexible sealing member. In consideration of suppression of crystallization, suppression of dark spots generated due to peeling of the cathode 14, extension of the life of the organic EL element 1, etc., the value is preferably about 1.0% or less.
The “water content” referred to here is a value measured by a technique based on ASTM (American Society for Testing and Materials) -D570.

  Examples of the resin base material constituting the flexible sealing member include ethylene tetrafluoroethyl copolymer (ETFE), high-density polyethylene (HDPE), expanded polypropylene (OPP), polystyrene (PS), polymethyl methacrylate (PMMA). ), Stretched nylon (ONy), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyimide, polyether styrene (PES), etc. can do. In addition, as a thermoplastic resin film, a multilayer film produced by co-extrusion of different types of films, a multilayer film produced by laminating a plurality of films with different stretching angles, if necessary, etc. You can also Moreover, when producing such a multilayer film, in order to obtain the physical properties required for the flexible sealing member, it is preferable to combine them in consideration of physical properties such as the density and molecular weight distribution of each film used.

The flexible sealing member is configured in consideration of suppression of crystallization of the organic compound layer 13, suppression of dark spots generated due to peeling of the cathode 14, extension of the lifetime of the organic EL element 1, and the like. The water vapor permeability of the barrier layer is preferably about 0.01 g / [m ² · day · atm] or less, and the oxygen permeability of the barrier layer is about 0.01 cm ³ / [m ² · day · atm] or less.

  As the material for forming the barrier layer, any material can be used as long as it has the above-described water vapor permeability and oxygen permeability. For example, the barrier layer can be composed of a coating made of an inorganic material such as silicon oxide, silicon dioxide, or silicon nitride. In order to improve the brittleness of the barrier layer, it is more preferable that the barrier layer is composed of a hybrid film (multilayer film) obtained by laminating the film made of the inorganic material and the film made of the organic material. In this case, the order of laminating the film made of the inorganic material and the film made of the organic material is arbitrary, but it is preferable to laminate a plurality of both alternately.

  In addition, as a method for forming the barrier layer, any method can be used as long as the barrier layer can be formed on the resin layer. For example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma polymerization method (see JP 2004-68143 A), Techniques such as plasma CVD, laser CVD, thermal CVD, and coating can be used.

<< Manufacture of organic EL elements >>
Next, the manufacturing process of the organic EL element 1 according to this embodiment will be described.
FIG. 3 is a schematic view of a process of manufacturing the organic EL element 1 by roll-to-roll using a substrate original winding (roll) with an ITO pattern.

[Organic EL device manufacturing equipment]
The organic EL element 1 according to the present embodiment is produced using, for example, a continuous vacuum film forming apparatus 40 as shown in FIG.

The continuous vacuum film forming apparatus 40 mainly includes an original winding roll 42, a decompression chamber R10, a vacuum film forming chamber R20, a vacuum film forming chamber R30, a pressure adjusting chamber R40, a laminating chamber R50, and a winding chamber R60. .
Each processing chamber is connected through gate slits A and B, gate valves C and D, and gate E, respectively.
The element substrate 11 with the electrode (anode 12) is conveyed from the original winding roll 42 to the winding chamber R60 via the guide rolls 60 to 86.

The decompression chamber R10 has a front chamber R12 and an accumulation chamber R14.
A slit roll 44 is provided between the front chamber R12 and the accumulation chamber R14.

The vacuum film formation chamber R20 includes a front chamber R21, a first film formation chamber R22, an accumulator chamber R23, a second film formation chamber R24, and a front chamber R25.
Vapor deposition boats 46 and 50 are provided in the first film formation chamber R22 and the second film formation chamber R24, respectively.
The accumulator chamber R23 has an accumulator mechanism that absorbs the processing speed, and an accumulator roll 48 is provided.

The vacuum film formation chamber R30 has a front chamber R32, a third film formation chamber R34, and a front chamber R36.
A vapor deposition boat 52 is provided in the third film formation chamber R34.

  An accumulator roll 54 is provided in the pressure adjustment chamber R40.

  In the laminating chamber R50, an original winding roll 56 of the sealing base material 30 with an adhesive is provided.

  In the winding chamber R60, an original winding roll 58 around which the continuous body of the manufactured organic EL element 1 is wound is provided.

[Method of manufacturing organic EL element]
First, the electrode-attached element substrate 11 unwound from the original winding roll 42 is transported to the front chamber R12 through the slit between the guide rolls 60 and 61, and further to the vacuum chamber R14 via the slit roll 44. The element substrate 11 under atmospheric pressure is continuously conveyed under vacuum sequentially. In the accumulation chamber R12, the web (substrate) processing length in the process is secured by the accumulator.
The degree of decompression of the front chamber R12, the accumulation chamber R14, etc. is maintained in the range of 1 × 10 ^{−7 to} 100 Pa, and the degree of decompression sequentially increases with the front chamber R12, the accumulation chamber R14, and a vacuum film formation chamber R20 described later. In the vacuum film formation chamber R20, the degree of pressure reduction is generally 10 ⁻³ to 10 ⁻¹ Pa.

Next, the element substrate 11 is continuously transferred to the vacuum film forming chamber R20 through the gate slit A. In the gate slit A, the differential pressure between the decompression chamber R10 and the vacuum film formation chamber R20 is adjusted. Although details are omitted, a slit roll may be used to adjust the differential pressure. Along with these, when the pressure difference between the decompression chamber R10 and the vacuum film formation chamber R20, which is a high vacuum, is large, a buffer region composed of a plurality of chambers is provided.
Each film formation chamber and the front chamber are independently evacuated.
In the first film formation chamber R22, the organic compound layer 13 is formed by vapor deposition on the element substrate 11, and in the second film formation chamber R24, metal vapor deposition is performed to form the cathode. Each film forming chamber is maintained in a range of a reduced pressure of 1 × 10 ⁻⁷ to 10 × 10 ⁻¹ Pa.
Next, the element substrate 11 formed up to the cathode 14 is transferred through the gate slit B to the vacuum film formation chamber R30. The gate slit B, like the gate slit A, adjusts the degree of vacuum together with the buffer mechanism, but further has a valve mechanism.

  In the third film forming chamber R34, an inorganic film is formed by sputtering, and then the element substrate 11 is transferred to the pressure adjusting chamber R40.

  In the pressure adjustment chamber R40, with the gate valve C opened, the gate valve D on the outlet side of the pressure adjustment chamber R50 is closed, the product web is accumulated in an accumulator, the gate valve C is closed, and the pressure is adjusted with an inert gas. Then, the gate valve D is opened and conveyed to the laminating chamber R50.

Next, in the laminating chamber R50, the sealing base material 30 with adhesive is unwound from the original winding roll 56 via the guide roll 87, and the guide rolls 84 and 85 are pressure bonded to the element substrate 11 formed up to the inorganic film. (Laminator), through a primary curing step by light or heat as necessary (not shown), transported to the winding chamber R60 and wound around the original winding roll 58.
In the primary curing step, the adhesive layer 20 may not be completely cured, but may be cured to such an extent that moisture or the like can be prevented from entering.
The degree of cure (reaction rate) in the primary curing step is preferably 5 to 30%, more preferably 5 to 15%. When the reaction rate is 5% or less, sufficient resistance to moisture or the like cannot be obtained, and when it exceeds 30%, the end of the element is peeled off when being installed on the installation target.
In addition, "reaction rate" represents the ratio of the reaction heat amount after hardening measured with the differential scanning calorimetry (DSC) with respect to the initial reaction heat amount.

  Finally, as shown in FIG. 4, each organic EL element is cut by cutting a continuous body of the organic EL elements 1 wound around the original winding roll 58 at a predetermined size, for example, at the position of the cutting line S. 1 is obtained.

The organic EL element 1 obtained as described above is deformed (curved) in accordance with the curved surface shape or the like of the installation object, and then secondarily cured by heat or light irradiation and completely sealed.
The degree of cure (reaction rate) in the secondary curing step is preferably 70% or more.
The side opposite to the installation object is the light extraction side of the organic EL element 1.
Further, the secondary curing step may be performed a plurality of times, and in this case, an element with higher sealing ability is obtained.

  The organic EL element 1 that has undergone only primary curing may be hermetically packaged and opened before the secondary curing step if necessary. In this case, the resistance to moisture and the like of the organic EL element 1 that has undergone only primary curing can be maintained over a long period of time.

  Further, when a mixture of a thermosetting adhesive and an ultraviolet curable adhesive is used as the sealing adhesive, for example, curing by heat in the primary curing process and curing by ultraviolet irradiation in the secondary curing process. Depending on the situation, it is possible to use different curing methods.

<Configuration of organic EL panel>
As shown in FIG. 5, the organic EL panel 100 is configured by tiling a plurality of organic EL elements 1 that are primarily cured via an adhesive layer 104 on a fixing substrate 102.
The organic EL elements 1 are electrically connected to each other, and there are a series connection method and an individual power supply method as connection methods.

Hereinafter, the organic EL panels connected by the respective connection methods will be described.
Hereinafter, the organic EL panel 100 using the six organic EL elements 1 will be described, but the present invention is not particularly limited thereto.

(1) Series connection method When the organic EL panel 100 is a series connection method, the organic EL elements 1 to 6 are arranged as shown in FIG. Here, the organic EL elements 2 to 5 are synonymous with the organic EL element 1.

An extraction electrode 12a of the anode 12 and an extraction electrode 14a of the cathode 14 are arranged to face each other at the element end portions (two opposing sides) of the organic EL elements 1 to 6.
The extraction electrodes 12a and 14a of the organic EL elements 1 to 6 are alternately arranged along the left-right direction X, and the extraction electrode 12a of the organic EL element 2 is adjacent to the extraction electrode 14a of the organic EL element 1. Are arranged.

As shown in FIG. 7A, the extraction electrodes 12 a and 14 a adjacent in the left-right direction X are electrically connected by the terminal member 106.
The two organic EL elements 1 and 4 at the left end are connected to each other by the terminal member 108. The other end of the terminal member 108 is connected to a power feeding unit (not shown). Similarly, the two organic EL elements 3 and 6 at the right end are also connected by the terminal member 110, and the other end of the terminal member 110 is connected to a power feeding unit (not shown).

  As shown in FIG. 7B, a conductive adhesive 112 is applied on the extraction electrodes 12a and 14a of the organic EL elements 1 to 6. The organic EL elements 1 to 6 and the terminal members 106, 108, and 110 are electrically connected through the conductive adhesive 112.

(2) Individual Power Supply Method When the organic EL panel 100 is set to the individual power supply method, extraction electrodes 12a and 14a are formed on each side of the organic EL element as shown in FIG. The extraction electrodes 12 a and 14 a of the organic EL elements 1 to 6 are alternately arranged along the left-right direction X and the front-rear direction Y.

As shown in FIG. 9A, the extraction electrode 12 a and the extraction electrode 14 a of the organic EL element 1 are electrically connected via the terminal member 114. As for the organic EL elements 2 to 6, similarly to the organic EL element 1, the extraction electrode 12 a and the extraction electrode 14 a are electrically connected independently. The other end of the terminal member 114 is connected to a power feeding unit (not shown).
As shown in FIG. 9B, the organic EL elements 1 to 6 and the terminal member 114 are electrically connected through a conductive adhesive 112.

  In the example illustrated in FIGS. 5 to 9, the configuration example in which the plurality of organic EL elements 1 to 6 are supported using the fixing substrate 102 has been described, but the present invention is not limited to this. For example, when the side portions of two organic EL elements adjacent to each other are bonded together with an adhesive (support member), the fixing substrate 102 may not be used.

  Hereinafter, each part of the organic EL panel 100 will be described.

[Fixing substrate]
As the fixing substrate 102, for example, a material such as glass, quartz, metal, resin, or a flat plate member made of a composite member thereof can be used.
Those using a flexible resin material, thin film glass, or metal foil are preferred.
When light is not emitted from the fixing substrate 102 side, a metal foil may be used for the fixing substrate 102.

Examples of the resin material that can be used for the fixing substrate 102 include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene (PE), polypropylene (PP), polycarbonate (PC), nylon, Examples include acrylic and cellophane.
Examples of the metal foil that can be used for the fixing substrate 102 include aluminum foil, copper foil, and stainless steel foil. A composite sheet laminated with a resin sheet can also be used.

  The fixing substrate 102 may be a printed circuit board including electronic components such as a drive circuit for driving the organic EL element 1 to emit light and a wiring terminal for connecting to the power feeding unit. The printed board may be made of any material, but a flexible material such as a flexible wiring board (FPC) is desirable.

[Adhesive layer]
As the adhesive layer 104, for example, an adhesive, an adhesive tape, or the like can be used.
Examples of the adhesive include thermosetting adhesive resins such as thermoplastic resins, epoxy resins, acrylic resins, and silicone resins.
As an adhesive tape, the adhesive tape using a pressure sensitive adhesive is mentioned.

  Examples of the bonding between the fixing substrate 102 and each of the organic EL elements 1 to 6 include a roll laminate and a diaphragm type vacuum lamination. From the viewpoint of ensuring adhesion and suppressing voids, bonding under a vacuum is possible. preferable.

[Terminal members]
The terminal members 106, 108, 110 and 114 may be made of any material as long as they can be electrically connected, but a flexible material such as a flexible wiring board (FPC) is desirable.
As a method of joining the terminal members 106, 108, 110, 114 and the extraction electrodes 12a, 14a, soldering, conductive paste, conductive ink, ACF (anisotropic conductive film), ACP (anisotropic conductive paste), or the like can be used. Can be mentioned.
As a method for joining the terminal members 108, 110, and 114 to the power feeding portion, thermocompression bonding using a heat tool is generally used.

[Protective member]
It is preferable to arrange a protective member at the electrode connection portion, which is a joint portion between the terminal member 106 and the like and the extraction electrodes 12a and 14a, in order to secure chemical strength against mechanical strength and corrosion.
As a method, in the case of the organic EL panel 100 of the series connection method, a method in which the protective resin 116 is disposed on the electrode connecting portion as shown in FIG. 10 or at least around the electrode connecting portion of the fixing substrate 102 as shown in FIG. And a method of protecting the substrate by bonding the protective substrate 118 together, and a combination thereof.

The protective resin 116 may be made of any material as long as it can protect the electrode connection portion, but is preferably an epoxy-based or silicone-based cured resin.
The method of disposing the protective resin 116 on the electrode connecting portion is to form a pattern of the protective resin 116 at the joint between the extraction electrodes 12a, 14a of the organic EL elements 1 to 6 and the terminal member 106, etc. Dispensers, inkjets, and screen printing are common.

As the protective substrate 118, for example, a flat member made of a material such as glass, quartz, metal, resin, or a composite member thereof can be used. It is desirable to use a flexible resin material, thin film glass, or metal foil.
Examples of the resin material that can be used for the protective substrate 118 include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene (PE), polypropylene (PP), polycarbonate (PC), nylon, Examples include acrylic and cellophane. Further, it is preferable that the protective base material 118 using a resin material is provided with a gas barrier layer for preventing permeation of moisture and oxygen.
Examples of the metal foil that can be used for the protective substrate 118 include aluminum foil, copper foil, and stainless steel foil. A composite sheet laminated with a resin sheet can also be used.

For example, the protective substrate 118 is bonded to the entire surface or a part of the fixing substrate 102 and the organic EL elements 1 to 6 are tiling. It is formed by filling an adhesive 120 such as an epoxy-based or silicone-based cured resin or a thermoplastic resin such as polyethylene between the fixing substrate 102.
The adhesive 120 may be filled on either or both of the fixing base material 102 side and the protective base material 118 side on which the organic EL elements 1 to 6 are tiled. For example, the adhesive 120 is previously applied to the protective base material 118. A laminated protective base material 118 with an adhesive may be made and bonded to the fixing base material 102 on which the organic EL elements 1 to 6 are arranged.

  The laminating of the fixing base material 102 on which the organic EL elements 1 to 6 are disposed and the protective base material 118 includes a roll laminate and a diaphragm type vacuum laminate, and in order to ensure adhesion and suppress voids, Bonding under vacuum is preferred.

  The organic EL panel 100 obtained as described above is deformed (curved) according to the curved surface shape or the like of the object to be installed, and then secondarily cured the organic EL panels 1 to 6 by heat or light irradiation. Completely sealed.

According to the above embodiment, the organic EL element 1 is completely cured (sealed) by the secondary curing after being installed on the object having a curved surface shape after the primary curing and then being deformed. Further, peeling of the end portion of the element due to tension such as bending can be prevented. That is, even if the organic EL element 1 is deformed, the element performance is not deteriorated, and it is possible to install the object on an installation object having various shapes.
Moreover, the sealing method can be applied to the organic EL element 100 and the organic EL panel 100 including the plurality of organic EL elements 1, and the handling can be simplified during transportation.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these.

<< Preparation of organic EL element sample >>
(1) Preparation of Sample 1-1 As a transparent element substrate, a polyethylene terephthalate film (PET film) having a thickness of 100 μm, a width of 150 mm, and a length of 500 m formed with a gas barrier film (Example 1 of JP-A-2007-83644) And a mask pattern is formed by sputtering of 120 nm thick ITO (Indium Tin Oxide) under a vacuum environment condition of 5 × 10 ⁻¹ Pa under a vacuum environment condition of 5 × 10 ⁻¹ Pa. An anode having a size of 10 mm × 10 mm having both ends in the width direction of the substrate was continuously formed at regular intervals and wound up.

The substrate original winding with the ITO pattern is attached to the feeding side (original winding roll) of the continuous vacuum film forming apparatus (see FIG. 3), and in the first film forming chamber, α-NPD (40 nm), CBP (containing 6% of Ir (ppy) ₃ as a co-deposition component) (35 nm), BAlq (5 nm), Alq ₃ (40 nm), and lithium fluoride (0.5 nm) were deposited.

Furthermore, after depositing 110 nm of aluminum in the second deposition chamber, 200 nm of silicon nitride (SiN _x ) was deposited by sputtering in the third deposition chamber.
Thereafter, in the laminating chamber, laminating is performed in a dry nitrogen atmosphere using an aluminum foil coated with 30 μm of sealing resin (thermosetting adhesive) and a PET laminate film (aluminum foil thickness 30 μm, PET thickness 50 μm) and heated. Then, after the primary curing (80 ° C., 15 minutes), the film was wound up to form the original winding of the continuous body of organic EL elements.

  A flexible organic EL element having a size of 150 mm × 150 mm was produced by cutting the original winding serving as a continuum of the organic EL element into a predetermined size in a separate process.

The obtained organic EL element is held on the surface of a cylindrical member having a diameter of 400 mm with the light emitting surface facing outward, and the element is heated from the surface with a heater and subjected to secondary curing (100 ° C., 30 minutes). An element sample 1-1 was obtained.
The reaction rate of the sealing adhesive in the primary curing and the secondary curing (primary curing with respect to the initial reaction heat amount, or the reaction heat amount after the secondary curing) is as shown in Table 1. The amount of reaction heat was measured by differential scanning calorimetry (DSC).

(2) Production of Sample 1-2 Sample 1-2 was produced in the same manner as in Production of Sample 1-1, except that the element substrate was changed from a barrier film to thin film glass (100 μm).

(3) Production of Sample 1-3 Sample 1-3 was produced in the same manner as in Production of Sample 1-2, except that the adhesive was changed to UV curable.

(4) Preparation of sample 1-4 In the preparation of sample 1-1, after the primary curing, the element was sealed with barrier packaging, opened again, the element was placed on a curved surface, and then the secondary curing was performed in the same manner. Sample 1-4 was prepared.

(5) Production of Sample 1-5 Sample 1-5 was produced in the same manner as in Production of Sample 1-1, except that a pressure-sensitive adhesive was placed around the thermosetting adhesive during sealing.

(6) Preparation of Samples 1-6 to 1-9 Sample 1 was prepared in the same manner as in Preparation of Sample 1-1 except that the reaction rates in primary curing and secondary curing were changed as shown in Table 1. 6-1-9 were produced.

(7) Production of Sample 1-10 In production of Sample 1-1, Sample 1-10 was produced in the same manner except that the secondary curing was not performed after the curved surface was placed.

(8) Production of Sample 1-11 In the production of Sample 1-1, the first curing after sealing lamination was heated to 100 ° C. for 30 minutes (reaction rate 80%). Sample 1-11 was produced in the same manner except that the next curing was not performed.

(9) Preparation of sample 1-12 In preparation of sample 1-1, it was the same except that only the secondary curing after the installation (reaction rate 80%) was performed without heating the primary curing after sealing lamination. Thus, Sample 1-12 was produced.

(10) Preparation of Sample 1-13 In preparation of Sample 1-1, after primary curing, the element was sealed with barrier packaging, opened again, and the element was placed on a curved surface. Similarly, Sample 1-13 was produced.

<< Characteristic evaluation of organic EL elements >>
(1) Dark spot generation rate Each sample 1-1 to 1-13 was subjected to an environmental test under the following conditions.

The organic EL device placed on a cylindrical member having a diameter of 400 mm obtained by the above method is held in its shape while being held at 85 ° C. and 85% RH for 80 minutes, and then the temperature is lowered to −40 ° C. over 90 minutes (humidity) And the temperature was raised to 85 ° C. over 90 minutes (humidity 85% RH), and the cycle of holding for 80 minutes was repeated 100 cycles. Thereafter, this element was turned on using a constant voltage power source, and the occurrence rate (occurrence rate: initial DS occurrence rate) of the dark spot (non-light emitting portion) area was examined.
The dark spot occurrence rate was obtained by photographing the light emitting surface of the organic EL element and applying predetermined image processing to the image data.

The measured dark spot generation rate was discriminated based on the following five criteria, and the light emission performance of the organic EL element was evaluated.
The evaluation results are shown in Table 1.

1: Dark spot generation rate is 0% (no dark spots are generated)
2: Dark spot occurrence rate is greater than 0% and less than 5% 3: Dark spot occurrence rate is 5% or more and less than 8% 4: Dark spot occurrence rate is 8% or more and less than 10% 5: Dark spot occurrence rate is 10% or more

(2) Summary As shown in Table 1, Samples 1-1 to 1-9 of the present invention suppress the occurrence of dark spots as compared with Samples 1-10 to 1-13 of Comparative Examples. Recognize.
From the above, it is possible to divide the curing of the sealing adhesive layer into a primary curing process and a secondary curing process, and to cure the light emitting performance even when the sealing adhesive layer is placed in a condition that is easily deteriorated by the external environment. It turns out that it is useful for suppressing deterioration.

<< Preparation of organic EL panel sample >>
(1) Production of Sample 2-1 As a fixing substrate, a polyethylene terephthalate film (PET film) having a thickness of 100 μm and a size of 350 mm × 500 mm formed with a gas barrier film (see Example 1 of JP2007-83644A) Prepared by the method described above, and six organic EL element samples 1-1 were tiled on a fixing substrate and fixed with a pressure-sensitive adhesive tape using a pressure-sensitive adhesive. In addition, as sample 1-1, what performed only primary hardening (80 degreeC, 15 minutes) was used, and primary hardening was implemented on the conditions from which the reaction rate will be 10%.
A series connection type FPC was prepared as a terminal member, and fixed to each extraction electrode of the organic EL element by thermocompression bonding with ACF (Hitachi Chemical MF-331).
As protective material, prepare aluminum foil and PET laminate film (aluminum foil thickness 30 μm, PET thickness 50 μm) coated with 400 μm in size of 350 mm × 500 mm sealing resin (curing adhesive), and arrange the organic EL elements After fixing on the fixing substrate, a flexible organic EL panel was prepared by bonding together with a diaphragm vacuum laminate.

The obtained organic EL panel is held on the surface of a cylindrical member having a diameter of 400 mm with the light emitting surface facing outward, and the element is heated from the surface with a heater and subjected to secondary curing (100 ° C., 30 minutes). Panel sample 2-1 was obtained.
The secondary curing was performed under the condition that the reaction rate of the sealing adhesive was 80%.

(2) Preparation of Sample 2-2 In preparation of Sample 2-1, heating (100 ° C., 30 minutes) up to the secondary curing is performed by primary curing after sealing lamination of Sample 1-1 (reaction rate) 80%) Sample 2-2 was prepared in the same manner except that secondary curing was not performed.

(3) Preparation of Sample 2-3 In the preparation of Sample 2-1, only the secondary curing (reaction rate 80%) after installation was performed without heating the primary curing after the sealing lamination of Sample 1-1. Sample 2-3 was produced in the same manner as described above.

<< Characteristic evaluation of organic EL panel >>
In the same manner as in Example 1, environmental tests (measurement of dark spot occurrence rate) of Samples 2-1 to 2-3 were performed, and the light emission performance of the organic EL panel was evaluated based on the same criteria.
The evaluation results are shown in Table 2.

As shown in Table 2, it can be seen that Sample 2-1 of the present invention suppresses the generation of dark spots as compared with Samples 2-2 and 2-3 of Comparative Examples.
From the above, it can be seen that the sealing method in which the curing of the sealing adhesive layer of the organic EL element is divided into a primary curing step and a secondary curing step and is cured is also useful in the organic EL panel.

DESCRIPTION OF SYMBOLS 1 Organic EL element 10 Organic EL element main-body part 11 Element substrate 12 Anode 13 Organic compound layer 14 Cathode 15 Inorganic film 16 Inorganic insulating film 20, 22 Adhesive layer 30 Sealing base material 40 Continuous vacuum film-forming apparatus 42, 56, 58 Original roll 44 Slit roll 46, 50, 52 Deposition boat 54 Accum roll 60-86 Guide roll 100 Organic EL panel 102 Fixing substrate 104 Adhesive layer 106, 108, 110, 114 Terminal member 112 Conductive adhesive 116 Protective resin 118 Protective substrate 120 Adhesive R10 Decompression chamber R12 Front chamber R14 Accumulation chamber R20 Vacuum deposition chamber R21 Front chamber R22 First deposition chamber R23 Accumulator chamber R24 Second deposition chamber R25 Front chamber R30 Vacuum deposition chamber R32 Front chamber R34 Third deposition chamber R36 Front chamber R40 Pressure adjustment chamber R 50 Laminating chamber R60 Winding chamber A, B Gate slit C, D Gate valve E Gate S Cutting line X Left-right direction Y Front-back direction

Claims (6)

On the flexible element substrate, an organic electrolayer having a pair of electrodes, an organic compound layer having at least one light emitting layer between the electrodes, and further having an adhesive layer and a flexible sealing substrate. A method for sealing a luminescence element,
A primary curing step of curing the adhesive layer;
A step of curving said organic electroluminescence element,
A secondary curing step of curing the adhesive layer in a state where the organic electroluminescence element is curved ;
A method for sealing an organic electroluminescent element, comprising: In the sealing method of the organic electroluminescent element of Claim 1,
In the primary curing step, the reaction rate of the constituent material of the adhesive layer is 5 to 30%,
In the secondary curing step, the reaction rate of the constituent material of the adhesive layer is set to 70% or more. In the sealing method of the organic electroluminescent element of Claim 1 or 2 ,
The constituent material of the said adhesive bond layer is a thermosetting adhesive or an ultraviolet curable adhesive, The sealing method of the organic electroluminescent element characterized by the above-mentioned. In the sealing method of the organic electroluminescent element as described in any one of Claims 1-3,
A sealing method of an organic electroluminescence element, wherein after the primary curing step, the organic electroluminescence element is sealed and packaged and then opened before being bent . In the sealing method of the organic electroluminescent element as described in any one of Claims 1-4 ,
Sealing method of an organic electroluminescent device characterized by disposing an adhesive layer comprising a pressure sensitive adhesive on the side portion of the adhesive layer. On the flexible element substrate, an organic electrolayer having a pair of electrodes, an organic compound layer having at least one light emitting layer between the electrodes, and further having an adhesive layer and a flexible sealing substrate. A method for sealing an organic electroluminescence panel in which a plurality of luminescence elements are arranged,
A primary curing step of curing the adhesive layer;
Forming a plurality of organic electroluminescence elements to form an organic electroluminescence panel; and
A step of bending the organic electroluminescence panel,
A secondary curing step of curing the adhesive layer in a state where the organic electroluminescence panel is curved ;
A method for sealing an organic electroluminescence panel, comprising:

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