WO2011114882A1

WO2011114882A1 - Organic electroluminescent panel and production method for organic electroluminescent panel

Info

Publication number: WO2011114882A1
Application number: PCT/JP2011/054726
Authority: WO
Inventors: 正数遠西; 真人奥山
Original assignee: コニカミノルタホールディングス株式会社
Priority date: 2010-03-17
Filing date: 2011-03-02
Publication date: 2011-09-22
Also published as: JPWO2011114882A1

Abstract

Disclosed is a production method for an organic EL panel having an excellent lifespan and resistance against initial dark spots in the organic EL elements, as well as a high rectification ratio. Also disclosed is an organic EL panel. The organic EL panel production method, in which a contact sealing structure is formed by affixing a sealing substrate upon a substrate having an organic EL element formed thereon that is provided with a first electrode, an organic compound layer comprising a light-emitting layer, and a second electrode, and adhering the surfaces thereof together via a sealing material, is characterized in that said sealing material is a thermosetting resin or an ultraviolet-curing resin, and in that, once the sealing substrate has been affixed upon the substrate via the sealing material and the surfaces thereof have been adhered together, a step for cooling the substrates to 5˚C or lower is completed and said sealing material is subsequently hardened by applying heat or ultraviolet rays thereto, thereby producing the organic EL panel.

Description

Organic electroluminescence panel and method for manufacturing organic electroluminescence panel

The present invention relates to an organic electroluminescence panel and a manufacturing method thereof, and more particularly to an organic electroluminescence panel to which a solid sealing method using a sheet-like sealing material is applied and a manufacturing method thereof.

In recent years, organic electroluminescence devices using organic substances (hereinafter also referred to as organic EL devices) are promising for use as solid light-emitting, inexpensive large-area full-color display devices and writing light source arrays, and are actively researched. Development is in progress. The organic EL device includes a first electrode (anode or cathode) formed on a substrate, an organic compound layer (single layer portion or multilayer portion) containing an organic light emitting material laminated thereon, that is, a light emitting layer, It is a thin film type element having a second electrode (cathode or anode) laminated on the light emitting layer. When a voltage is applied to the organic EL element having such a configuration, electrons are injected into the organic compound layer from the cathode and holes are injected from the anode. It is known that light is obtained by releasing energy as light when the electrons and holes recombine in the light emitting layer and the energy level returns from the conduction band to the valence band.

As described above, since the organic EL element is a thin film type element, when an organic EL element in which one or a plurality of organic EL elements are formed on a substrate is used as a surface light source such as a backlight, a surface light source. It is possible to easily make the device provided with Further, when an organic electroluminescence display device is configured using an organic electroluminescence panel (hereinafter also referred to as an organic EL panel) in which a predetermined number of organic EL elements as pixels are formed on a substrate, the visibility is improved. There is an advantage that cannot be obtained by a liquid crystal display device, such as being high and having no viewing angle dependency.

However, organic substances such as organic light emitting materials used in organic EL elements are easily affected by moisture, oxygen, etc., and their performance deteriorates when stored in such an environment. In the atmosphere, the characteristics deteriorate rapidly, and a spot-like non-light emitting portion (hereinafter referred to as a dark spot) is generated on the organic EL element. In order to prevent this, an organic EL element is generally used by providing a sealing layer as the uppermost layer.

As a method for preventing the occurrence of these dark spots, for example, in Japanese Patent Laid-Open Nos. 5-182759, 5-36475, and 2002-43055, a metal container-type sealing material is used. A method of covering and sealing an organic EL element through an adhesive layer in a dry nitrogen atmosphere is described. However, in the method using these metal container-type sealing materials that are excellent in measures against dark spots, the effect depends mainly on the thickness of the container-type sealing material, and is required in the market. It is not suitable for manufacturing thin organic EL elements. For this reason, the manufacturing method of the thin organic EL element which has the same dark spot prevention effect as a container type sealing material has been examined until now. For example, Patent Document 1 proposes an organic electroluminescence panel using a sealing film that can form a thin organic EL element and has a barrier property. In Patent Document 1, instead of a sealing can, a flexible film having a barrier property (hereinafter also referred to as a sealing film) is used as a sealing member, and the organic EL element substrate and an adhesive are bonded together in a vacuum. Is disclosed. In addition, from the viewpoint of further improving the durability of the organic EL element, Patent Document 2 discloses a method for removing organic substances and modifying the surface by performing a dry cleaning process in addition to the dehydrating process of the sealing member. Are listed.

JP 2003-045652 A JP 2007-078552 A

However, the close-contact type sealing methods described in

Patent Documents

1 and 2 are relatively easy to mass-produce and can produce a thin organic EL element having a high sealing effect. Initial damage to the light emitting element due to (surface adhesion on the organic electroluminescence element) occurs, and the countermeasure is insufficient.

From such a situation, when manufacturing an organic EL panel in which an organic EL element is sealed by an adhesion type sealing method in which a sealing material is fixed through an adhesive, the performance of the organic EL element is not deteriorated. Therefore, it is desired to develop an organic EL panel manufacturing method and an organic EL panel with little reduction in production efficiency.

Therefore, an object of the present invention is to provide an organic electroluminescence panel manufacturing method and an organic electroluminescence panel which have excellent initial dark spot resistance and element lifetime of an organic EL element and have a high rectification ratio.

The above object of the present invention is achieved by the following configuration.

1. At least a first electrode, an organic compound layer including a light emitting layer, and a substrate on which an organic electroluminescence element having a second electrode is formed. In the manufacturing method of the organic electroluminescent panel to be formed, the sealing material is a thermosetting resin or an ultraviolet curable resin, and the organic electroluminescent panel is formed by bonding a sealing substrate on the substrate via the sealing material. A method for producing an organic electroluminescence panel, which is produced by subjecting a surface to adhesion, followed by a step of cooling to 5 ° C. or lower, and then applying heat or ultraviolet light to the sealing material to cure.

2. 2. The method of manufacturing an organic electroluminescence panel according to 1 above, wherein the substrate and the sealing substrate are both flexible substrates.

3. 3. The method for producing an organic electroluminescence panel according to 1 or 2, wherein the sealing substrate is a moisture-proof film having a metal foil.

4. 4. The method for producing an organic electroluminescence panel according to any one of 1 to 3, wherein the sealing material is an epoxy thermosetting resin.

5. The substrate is formed by bonding a sealing substrate on the substrate on which the organic electroluminescence element is formed via the sealing material and bonding the surface to each other, and then performing a process of cooling to 5 ° C. or less within 12 hours. The method for producing an organic electroluminescence panel according to any one of 1 to 4 above.

6. 6. The method for producing an organic electroluminescence panel according to any one of 1 to 5, wherein a treatment time in the step of cooling to 5 ° C. or lower is 2 hours or longer.

7. 7. The method for producing an organic electroluminescence panel according to any one of 1 to 6, wherein a treatment temperature in the step of cooling to 5 ° C. or lower is 0 ° C. or lower.

8. 8. An organic electroluminescence panel manufactured using the method for manufacturing an organic electroluminescence panel according to any one of 1 to 7 above.

According to the present invention, an organic electroluminescence panel having an excellent initial dark spot resistance and device lifetime of an organic EL device and having a high rectification ratio is obtained by using a close-contact type sealing method in which a sealing material is fixed through an adhesive. A method and an organic electroluminescence panel could be provided.

It is sectional drawing which shows an example of a structure of the organic electroluminescent panel of this invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail.

As a result of intensive studies in view of the above problems, the inventor of the present invention, on a substrate on which an organic electroluminescence element having at least a first electrode, an organic compound layer including a light emitting layer, and a second electrode is formed via a sealing material. In the manufacturing method of an organic electroluminescence panel in which a sealing substrate is bonded and bonded to each other to form a tightly sealed structure, the sealing material is a thermosetting resin or an ultraviolet curable resin, and the organic electroluminescence panel is After the sealing substrate is bonded onto the substrate via a sealing material and bonded to the surface, the sealing material is subjected to a step of cooling to 5 ° C. or lower, and then the sealing material is cured by applying heat or ultraviolet rays. The organic EL panel manufacturing method is characterized by excellent initial dark spot resistance and device life of organic EL devices, and has a high rectification ratio. Method of producing an organic electroluminescent panel capable of manufacturing an organic electroluminescent panel found that it is possible to realize a completed the invention.

Hereinafter, the details of the organic electroluminescence panel of the present invention and the manufacturing method thereof will be described.

〔substrate〕
As a substrate (hereinafter also referred to as a support substrate, a substrate, a base material, or a support) that can be used in the organic EL device according to the present invention, there is no particular limitation on the type, such as glass, plastic, metal, ceramic, etc. It may be transparent or opaque. In the case where light is extracted from the substrate side, the substrate is preferably transparent, and examples of the transparent substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable substrate is a resin film that can impart flexibility (also referred to as flexibility) to the organic EL element.

Examples of the resin film applicable as the substrate of the organic EL device according to the present invention include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, Cellulose acetate butyrate, cellulose acetate propionate (CAP), cellulose acetate phthalate (TAC), cellulose esters such as cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, Polycarbonate, norbornene resin, polymethylpentene, polyetherketone, polyimide, polyethersulfone ( ES), polyphenylene sulfide, polysulfones, polyether imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic or polyarylates, Arton (trade name, manufactured by JSR) or Apel (trade name, Cycloolefin-based resins such as Mitsui Chemicals).

On the surface of the resin film to be applied as the substrate, an inorganic film, an organic film, or a hybrid film of both may be formed, and the water vapor transmission rate (temperature: measured by a method according to JIS K 7129-1992). 25 ± 0.5 ° C., relative humidity: 90 ± 2% RH) is preferably a barrier film of 1 × 10 ⁻³ g / (m ² · 24 h) or less, and further according to JIS K 7126-1987. Oxygen permeability measured by a compliant method is 1 × 10 ⁻³ ml / m ₂ · 24 h · atm or less, water vapor permeability (temperature: 25 ± 0.5 ° C., relative humidity: 90 ± 2% RH) A high barrier film of 1 × 10 ⁻³ g / (m ² · 24 h) or less is preferable.

In order to make a high barrier film, the constituent material of the barrier film formed on the surface of the resin film may be any material that has a function of preventing the ingress of oxygen and moisture that induces deterioration of the organic EL panel. An inorganic film such as silicon oxide, silicon dioxide, or silicon nitride can be used. Furthermore, in order to improve the fragility of the inorganic film, it is more preferable to have a laminated structure of these inorganic film and a film made of an organic material. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic film and an organic film, It is preferable to laminate | stack both alternately several times.

The method for forming the barrier film is not particularly limited. For example, the 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 weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method and the like can be used, but a formation method using an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable. preferable.

[Functional layer (organic compound layer)]
As an organic compound layer in this invention, it has the structure by which the functional layer which consists of various organic compounds, such as a positive hole injection / transport layer / light emitting layer / electron injection / transport layer, was laminated | stacked as needed, for example. The simplest configuration is a structure consisting only of a light emitting layer.

(Hole injection / transport layer)
Examples of organic compound materials used for the hole injection / transport layer include phthalocyanine derivatives, heterocyclic azoles, aromatic tertiary amines, polyvinyl carbazole, polyethylenedioxythiophene / polystyrene sulfonic acid (PEDOT: PSS), and the like. A polymer material such as a representative conductive polymer is used.

(Light emitting layer)
Examples of the organic compound material used for the light emitting layer include carbazole-based light emitting materials such as 4,4′-dicarbazolylbiphenyl and 1,3-dicarbazolylbenzene, (di) azacarbazoles, 1,3 , 5-tripyrenylbenzene and the like, low molecular light emitting materials typified by pyrene light emitting materials, polyphenylene vinylenes, polyfluorenes, polyvinyl carbazoles and the like polymer light emitting materials. Of these, a low molecular weight light emitting material having a molecular weight of 10,000 or less is preferably used as the light emitting material.

The light-emitting material applied to the light-emitting layer may preferably contain about 0.1 to 20% by mass of a dopant. Examples of the dopant include known fluorescent dyes such as perylene derivatives and pyrene derivatives, and phosphorescence. Orthometalation represented by dyes such as tris (2-phenylpyridine) iridium, bis (2-phenylpyridine) (acetylacetonato) iridium, bis (2,4-difluorophenylpyridine) (picolinato) iridium, etc. There are complex compounds such as iridium complexes.

(Electron injection / transport layer)
As a constituent material of the electron injecting / transporting layer, there are metal complex compounds such as 8-hydroxyquinolinate lithium and bis (8-hydroxyquinolinato) zinc, and nitrogen-containing five-membered ring derivatives listed below. That is, oxazole, thiazole, oxadiazole, thiadiazole or triazole derivatives are preferred. Specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole, 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5-bis (1 -Phenyl) -1,3,4-oxadiazole, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) 1,3,4-oxadiazole, 2,5-bis ( 1-naphthyl) -1,3,4-oxadiazole, 1,4-bis [2- (5-phenyloxadiazolyl)] benzene, 1,4-bis [2- (5-phenyloxadiazolyl) -4-tert-butylbenzene], 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-thiadiazole, 2,5-bis (1-naphthyl) -1 , 3,4-thiadiazole, 1,4-bis [2- (5-phenyl) Asiazolyl)] benzene, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) -1,3,4-triazole, 2,5-bis (1-naphthyl) -1,3,4 -Triazole, 1,4-bis [2- (5-phenyltriazolyl)] benzene and the like.

As the organic compound material used for these light emitting layers and each functional layer, a material having a polymerization reactive group such as a vinyl group in the molecule is used, and a cross-linked / polymerized film is formed after film formation to form each functional layer. May be.

(Injection layer)
In addition, an injection layer may be formed between the electrode and the organic layer in order to reduce the drive voltage and improve the light emission luminance as necessary.

The injection layer includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

<Hole injection layer>
As an anode buffer layer (hole injection layer), a phthalocyanine buffer layer typified by copper phthalocyanine, an oxide buffer layer typified by vanadium oxide, an amorphous carbon buffer layer, a conductive polymer such as polyaniline (emeraldine) or polythiophene And a polymer buffer layer using

<Electron injection layer>
Examples of the cathode buffer layer (electron injection layer) include a metal buffer layer typified by strontium, aluminum, calcium, and magnesium, an alkali metal compound buffer layer typified by lithium fluoride, and an alkali typified by magnesium fluoride. Examples thereof include an earth metal compound buffer layer and an oxide buffer layer typified by aluminum oxide.

Each of the buffer layers (injection layers) is desirably a very thin film, and although depending on the material, the film thickness is preferably in the range of 0.1 to 100 nm. The injection layer may be a single layer or a plurality of layers.

In the organic EL device according to the present invention, each functional layer described above may be formed by a vacuum process, a dry process such as a sputtering process, or a wet process such as a coating or printing process. Also good.

[First electrode, second electrode]
In the organic EL device according to the present invention, in order to transmit emitted light, at least one of the first electrode and the second electrode constituting the organic EL device needs to be transparent or translucent. Furthermore, an organic EL element in which both the anode and the cathode are transparent can be obtained by using the first electrode as a transparent electrode and further producing a transparent or translucent second electrode.

As the first electrode according to the present invention, the cathode and the anode are not particularly limited and can be selected depending on the configuration of the organic EL element. Preferably, the first electrode is an anode using a transparent electrode. . For example, when used as an anode, it is preferably an electrode that transmits light from 380 nm to 800 nm. A material having a work function larger (deep) than 4 eV is suitable as a material, for example, a transparent conductive metal oxide such as indium tin oxide (ITO), SnO ₂ , or ZnO, or a metal such as gold, silver, or platinum. Thin films, metal nanowires, carbon nanotubes, and the like can be used.

For the first electrode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or the pattern accuracy is not so required (100 μm). As above, a pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material. Moreover, when using the compound which can be apply | coated like an organic electroconductivity compound, wet film forming methods, such as a printing system and a coating system, can also be used.

When light emission is extracted from the first electrode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the first electrode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material used, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

As a 2nd electrode which concerns on this invention, a cathode and an anode are not specifically limited, It can select according to an organic EL element structure. For example, when used as a cathode, it is preferable to use a metal, an alloy, an electrically conductive compound having a work function of 4 eV or less (shallow), and a mixture thereof as an electrode material. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the viewpoint of electrical bonding with the organic functional layer and durability against oxidation and the like, these metals and the second metal, which is a stable metal having a larger (deep) work function value than this, Mixtures such as magnesium / silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum alone and the like are suitable.

The second electrode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 nm to 200 nm.

If a highly reflective metal material is used as the second electrode, in the organic EL element, a part of the emitted light can be reflected and taken out to the outside. Also, an organic photovoltaic element (organic photovoltaic element, solar cell) ), The effect of increasing the optical path length is obtained by reflecting the light that has passed through the photoelectric conversion layer and returning it to the photoelectric conversion layer again, and in any case, an improvement in external quantum efficiency can be expected.

Furthermore, it may be a nanoparticle, nanowire, or nanostructure made of metal (eg, gold, silver, copper, platinum, rhodium, ruthenium, aluminum, magnesium, indium, etc.) or carbon. This highly dispersible paste is preferable because a transparent and highly conductive counter electrode can be formed by a coating method or a printing method.

[Sealant for sealing]
In the method for producing an organic EL panel of the present invention, a sealing material (also referred to as a sealing adhesive) used to form an adhesion sealing structure by laminating a substrate of an organic EL element and a sealing substrate and bonding the surfaces. ) Is a thermosetting resin or an ultraviolet curable resin.

The thermosetting resin and the ultraviolet curable resin applicable to the present invention are not particularly limited, but thermosetting resins such as epoxy resins, acrylic resins, and silicone resins are preferable, and moisture resistance and water resistance are more preferable. It is an epoxy thermosetting resin that has excellent properties and has little shrinkage when cured. In addition, as a method for forming the adhesive layer, a coating method such as roll coating, spin coating, screen printing, or spray coating can be used depending on a material to be applied. Moreover, in order to remove moisture contained in the adhesive layer, a desiccant such as barium oxide or calcium oxide may be mixed. The water content of the sealing adhesive according to the present invention is preferably 300 ppm or less, more preferably 0.01 to 200 ppm, and particularly preferably 0.01 to 100 ppm.

The moisture content may be measured by any method. For example, a volumetric moisture meter (Karl Fischer), an infrared moisture meter, a microwave transmission moisture meter, a heat-dry weight method, GC / MS, IR, DSC (Differential scanning calorimeter), TDS (Temperature desorption analysis), and other measuring methods. Further, using a precision moisture meter AVM-3000 (manufactured by Omnitech) or the like, the moisture content can be measured from the pressure increase caused by the evaporation of moisture.

In the present invention, the water content of the sealing material (sealing adhesive) is, for example, set in a nitrogen atmosphere having a dew point temperature of −80 ° C. or lower and an oxygen concentration of 0.8 ppm, and can be changed by changing the time. Can be adjusted to the conditions. Moreover, it can adjust also by placing in a vacuum state of 100 Pa or less and changing the time to dry. Moreover, although the adhesive agent for sealing can dry only an adhesive agent, it can also be dried after previously arrange | positioning to a sealing member.

[Sealing substrate]
Examples of the sealing substrate according to the present invention include metals such as stainless steel, aluminum, and magnesium alloys, resin films such as polyethylene terephthalate, polycarbonate, polystyrene, nylon, and polyvinyl chloride, and composite materials thereof, glass, and the like. Can be used as needed. In particular, in the case of a resin film, a material obtained by laminating a gas barrier layer composed of aluminum, aluminum oxide, silicon oxide, silicon nitride, or the like can be used as in the case of a resin substrate. In the present invention, the sealing substrate is preferably a metal foil from the viewpoint of flexibility and barrier properties. The metal foil used as the sealing substrate is not particularly limited in the type of metal. For example, copper (Cu) foil, aluminum (Al) foil, gold (Au) foil, brass foil, nickel (Ni) foil, titanium (Ti) foil, copper alloy foil, stainless steel foil, tin (Sn) foil, high nickel alloy foil, and the like. Among these various metal foils, a particularly preferred metal foil is an Al foil.

The metal foil mainly refers to a metal foil or film formed by rolling metal, etc., but a metal thin film formed by sputtering or vapor deposition on a polymer film, or a flow of conductive paste, etc. It may be a conductive film formed from a conductive electrode material.

Also, since the metal foil itself is inferior in mechanical strength, it is preferable to take a structure laminated with a polymer film in order to prevent the occurrence of pinholes. Various polymer materials described in “New development of functional packaging materials (Toray Research Center, Inc.)” can be used as the material of the polymer film used for lamination. For example, polyethylene resin, polypropylene resin, polyethylene terephthalate resin, polyamide resin, ethylene-vinyl alcohol copolymer resin, ethylene-vinyl acetate copolymer resin, acrylonitrile-butadiene copolymer resin, cellophane resin, vinylon Resin, vinylidene chloride resin and the like.

Each resin such as polypropylene resin, polyethylene terephthalate resin, and nylon resin may be stretched and further coated with a vinylidene chloride resin. In addition, a polyethylene resin having a low density or a high density can be used.

A generally used laminating machine can be used as a method of laminating a polymer film on one side of a metal foil. As the adhesive, polyurethane-based, polyester-based, epoxy-based, acrylic-based adhesives and the like can be used. You may use a hardening | curing agent together as needed. A hot melt lamination method, an extrusion lamination method and a coextrusion lamination method can also be used, but a dry lamination method is preferred.

In addition, when the metal foil is formed by sputtering or vapor deposition and is formed from a fluid electrode material such as a conductive paste, it may be produced by a method of forming a metal foil on a polymer film as a base material. Good.

In the present invention, the metal foil used as the sealing substrate preferably has a thickness of 9 to 500 μm, and a polymer film is laminated thereon, and the thickness of the polymer film is 10 to 100% of the metal foil. Preferably there is.

[Configuration of organic EL panel, sealing method]
FIG. 1 is a cross-sectional view showing an example of the configuration of the organic EL panel of the present invention.

In FIG. 1, an organic EL element including a first electrode 2, an organic EL layer (organic compound layer) 3 including a light emitting layer, and a second electrode 4 is formed on a resin substrate 1. A sealed organic electroluminescence (EL) panel P having a configuration in which a sealing substrate 5 is sealed at its end by an adhesive layer 6 is shown.

In the method of close sealing (solid sealing), as the sealing substrate, for example, a polyethylene terephthalate film with a thickness of 50 μm and an aluminum foil laminated with a thickness of 30 μm, for example, can be used. Using this as a sealing substrate, a sealing adhesive uniformly applied to the aluminum surface using a dispenser is placed in advance, the resin substrate 1 and the sealing substrate 5 are aligned, and then both are crimped together. After bonding (0.1 to 3 MPa), heat curing is performed at a temperature in the range of 80 to 160 ° C., and close sealing (solid sealing) is performed. The pressure-bonding time is appropriately set depending on the type of sealing adhesive, the applied amount, the applied area, etc., but the pressure is temporarily bonded within a range of about 0.1 to 3 MPa. At this time, a heated crimping roll can be used to eliminate voids remaining inside. As described above, the solid sealing is a form in which there is no space between the sealing member and the organic EL element substrate and the resin is cured with a cured resin.

Depending on the type and amount of the sealing adhesive, the heating temperature necessary for curing the adhesive layer can be set as appropriate, but is preferably 50 ° C. or higher and 200 ° C. or lower, more preferably 80 ° C. or higher, It is the range of 160 degrees C or less. Further, by heating for 1 minute or more and 1 hour or less, the curing (crosslinking reaction) proceeds and adheres in the case of a thermosetting resin. Also in the case of a photo-curing adhesive, the curing (adhesion) speed can be increased by heating after light irradiation.

[Step of cooling to below 5 ° C]
In the present invention, in the method of manufacturing an organic EL panel in which a sealing substrate is bonded to an organic EL element substrate through an adhesive and bonded to a surface to form a tightly sealed structure, the sealing material is a thermosetting resin or It is an ultraviolet curable resin. After a sealing substrate is pasted on the substrate through a sealing material and bonded to the surface, after passing through a process of cooling to 5 ° C. or less, heat or ultraviolet light is applied to the sealing material. It is characterized by being manufactured by curing.

In the conventional method in which the sealing material is heat-cured as it is after the surface adhesion, initial damage to the organic EL element occurs, but it is manufactured through a process of cooling to 5 ° C. or lower before heat-curing, which is a feature of the present invention. As a result, it was surprisingly found that the initial damage to the organic EL element was reduced.

Although the mechanism by which the above effects are manifested is not clear by the manufacturing process defined in the present invention, since the second electrode is not a completely dense film, the adhesive component penetrates into the minute gaps of the second electrode. Therefore, although it is easy to cause micro-peeling at the interface between the second electrode and the organic compound layer by heat curing, penetration of the adhesive component is suppressed by passing through a cooling step before heat curing, and cooling stays. Thus, it is presumed that only the curing in the minute voids progressed, and the minute peeling at the interface between the second electrode and the organic compound layer was suppressed even when heat curing was performed later.

The reason for the hardening of the adhesive in the minute gap due to the cooling stay is unknown, but it is possible that the minute defect of the second electrode has a catalytic action for promoting the hardening of the thermosetting adhesive.

After the sealing substrate is bonded and surface-adhered, the time until the process of cooling to 5 ° C. or less according to the present invention is preferably as short as possible, but is preferably within 12 hours, more preferably 10 seconds or more. Further, it is more preferably within 6 hours, particularly preferably within 1 minute and within 4 hours.

Further, the residence time of the organic EL panel in the step of cooling to 5 ° C. or less according to the present invention is preferably 1 hour or more, more preferably 2 hours or more and 8 days or less, still more preferably 1 day or more and 8 days or less. is there.

The temperature in the cooling step according to the present invention is 5 ° C. or less, preferably 0 ° C. or less, more preferably −20 ° C. or more and 0 ° C. or less.

[Light extraction material]
In the present invention, it is preferable to have a light extraction member between the flexible substrate and the second electrode or at any location on the light emission side from the flexible substrate.

In the present invention, examples of the light extraction member include a prism sheet, a lens sheet, and a diffusion sheet. Further, a diffraction grating or a diffusion structure introduced into an interface or any medium that causes total reflection can be used.

Usually, in an organic electroluminescence element that emits light from a substrate, a part of the light emitted from the light emitting layer causes total reflection at the interface between the substrate and air, causing a problem of loss of light. In order to solve this problem, prismatic or lens-like processing is applied to the surface of the substrate, or prism sheets, lens sheets, and diffusion sheets are affixed to the surface of the substrate, thereby suppressing total reflection and light extraction efficiency. To improve.

Also, in order to increase the light extraction efficiency, a method of introducing a diffraction grating or a method of introducing a diffusion structure in an interface or any medium that causes total reflection is known.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

<< Production of organic EL panel >>
[Production of Organic EL Panel 101]
(Process of forming a gas barrier layer on a flexible substrate)
A 125 μm thick polyethylene terephthalate film (Teijin-DuPont film, hereinafter abbreviated as PET), stored in advance at a dew point of −65 ° C. and in an inert gas atmosphere at a pressure of 80 Pa and subjected to dehydration and deoxygenation ) On one side of a flexible substrate provided with an acrylic clear hard coat layer having a film thickness of 5 μm on both sides according to a conventional method, according to the method described in the examples of JP-A-2007-83644. A gas barrier layer was formed by a treatment method. That is, the roll electrode type atmospheric pressure plasma discharge treatment apparatus shown in FIG.

Specifically, a gas barrier layer having a structure in which an adhesion layer / ceramic layer / adhesion layer / ceramic layer were laminated in this order was formed on one surface of the flexible base material under the atmospheric pressure plasma treatment conditions shown below. Each film thickness is 200 nm for the adhesion layer and 25 nm for the ceramic layer. The holding temperature of the flexible substrate during film formation was 140 ° C.

<Ceramic layer formation conditions>
Discharge gas: N ₂ gas Reaction gas 1: Oxygen gas 5% of the total gas
Reaction gas 2: TEOS (tetraethoxysilane) is 0.1% of the total gas
Low frequency side power supply: frequency = 80 kHz, power density = 10 W / cm ²
High frequency side power supply: frequency = 13.56 MHz, output density = 10 W / cm ²
<Formation condition of adhesion layer>
Discharge gas: N ₂ gas Reaction gas 1: 1% of hydrogen gas with respect to the total gas
Reaction gas 2: 0.5% TEOS (tetraethoxysilane) with respect to the total gas
Low frequency side power supply: frequency = 80 kHz, power density = 10 W / cm ²
High frequency side power supply: frequency = 13.56 MHz, output density = 5 W / cm ²
(Process of forming an electrode layer on a flexible substrate)
Next, the PET film on which the gas barrier layer is formed is cut out to 100 mm × 100 mm, indium tin oxide (ITO) is used as a target material, and gas pressure is used using argon containing 5% by volume of oxygen as a sputtering gas in a vacuum chamber. Was set to 0.5 Pa, and an ITO film was patterned as an electrode layer on the gas barrier layer by sputtering under the condition that the thickness was 110 nm. This was subjected to ultrasonic cleaning with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was further performed for 5 minutes.

(Process of forming organic compound layer)
On the flexible base material on which the gas barrier layer and the electrode layer are formed, poly (3,4-ethylenedioxythiophene) -polystyrene sulfonic acid (manufactured by PEDOT / PSS Bayer, Baytron P Al 4083) is added with pure water. A solution diluted to% was formed into a film by spin coating at 3000 rpm for 30 seconds, and then dried at 150 ° C. for 1 hour to form a 30 nm-thick hole transport layer.

After drying the hole transport layer, a light emitting layer coating solution having the following composition is further prepared to 1 ml, and spin-coated in a glove box having a moisture concentration of 1 ppm or less, an oxygen concentration of 10 ppm or less, and a temperature of 26 ° C. A light emitting layer having a thickness of about 25 nm was formed.

<Coating solution for light emitting layer>
Solvent: 100% by mass of toluene
Host material: HA 1% by mass
Blue material: Ir-A 0.10% by mass
Green material: Ir (ppy) ₃ 0.004 mass%
Red material: Ir (piq) ₃ 0.005 mass%
Next, the following electron transport layer coating solution was prepared, and applied with a spin coater under conditions of 1500 rpm and 30 seconds to provide an electron transport layer. Using this electron transport layer coating solution, coating was performed on a separately prepared substrate under the same conditions, and the film thickness was measured. As a result, it was 20 nm.

<Coating liquid for electron transport layer>
2,2,3,3-tetrafluoro-1-propanol 100ml
ET-A 0.50g

Further, the flexible base material on which the electron transport layer was formed was transferred to a vacuum deposition apparatus, the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and 10 nm of lithium fluoride and a cathode as a cathode buffer layer on the electron transport layer. As a result, an organic EL element 1 was fabricated by sequentially depositing aluminum 110 nm layers.

(Sealing substrate)
Next, an aluminum foil laminated with a polyester sheet was produced as a sealing substrate.

Using a 30 μm thick aluminum foil (manufactured by Toyo Aluminum Co., Ltd.), a 25 μm thick polyethylene terephthalate (PET) film is used on this mat surface with an adhesive for dry lamination (two-component reaction type urethane adhesive). Laminated (adhesive layer thickness 1.5 μm). The surface roughness Ra of the cut surface (mat surface) of this aluminum foil was 470 nm, and the Ra of the polished surface was 1 nm or less.

(Production of organic EL panel)
Next, the aluminum foil laminated with the polyethylene terephthalate prepared above was cut into approximately the same size (100 mm × 100 mm) as the PET substrate on which the organic EL element 1 was formed, and on the glossy surface (opposite side of the PET laminate surface), A thermosetting adhesive composed of agent a, agent b and agent c was applied to produce a sealing substrate with a sealing material.

<Thermosetting adhesive composition: Epoxy adhesive>
Agent a) Bisphenol A diglycidyl ether (DGEBA)
b) Dicyandiamide (DICY)
c agent) Epoxy adduct type curing accelerator The thermosetting adhesive is uniformly applied along the adhesive surface (shiny surface) of aluminum foil laminated with polyethylene terephthalate using a dispenser, and has a moisture concentration of 1 ppm or less, oxygen The sample was left in a glove box having a concentration of 10 ppm or less and a temperature of 26 ° C. for 12 hours. The thickness of the adhesive layer was 20 μm, and the water content measured by the Karl Fischer method was 50 ppm or less.

The organic EL element 1 is formed so that the extraction electrode is exposed from the thus prepared sealing substrate with adhesive in a glove box having a moisture concentration of 1 ppm or less, an oxygen concentration of 10 ppm or less, and a temperature of 26 ° C. The adhesive surface was placed in close contact with the PET substrate so as to cover it, and the sealing substrate was pressure-bonded (pressure 0.15 MPa, time 30 seconds) to be temporarily bonded. Next, after storing in an environment of 26 ° C. for 1 hour, the organic EL panel is immediately moved onto a hot plate, heated (temperature 120 ° C., 30 minutes) to thermally cure the thermosetting adhesive, and the organic EL panel 101 Was made.

[Production of organic EL panels 102 and 103]
In the production of the organic EL panel 101, organic EL panels 102 and 103 were produced in the same manner except that the storage time at 26 ° C. after temporary bonding was changed to 24 hours and 120 hours, respectively.

[Production of organic EL panel 104]
In the production of the organic EL panel 101, after temporary bonding, it was stored in an environment of 26 ° C. for 1 hour, and then subjected to a cooling process at 10 ° C. for 120 hours, followed by thermosetting treatment. Similarly, an organic EL panel 104 was produced.

[Production of organic EL panels 105 to 113]
In the production of the organic EL panel 104, the storage time at 26 ° C. until the cooling process is performed after temporary bonding, the cooling temperature in the cooling step, and the cooling time are the same except that the conditions shown in Table 1 are changed. Thus, organic EL panels 105 to 113 were produced.

<< Evaluation of organic EL panel >>
Each of the produced organic EL panels 101 to 113 was evaluated according to the following method.

[Evaluation of rectification ratio]
+ 5V (forward direction) and -5V (reverse direction) are applied from the take-out electrode of each organic EL panel produced above with a low-voltage power supply (DC Co., Ltd., DC voltage / current source R6243), and the current at that time The value was measured, the ratio of the forward / reverse current value (rectification ratio = forward current value / reverse current value) was determined and judged according to the following rank.

A: The rectification ratio is 1000 or more. O: The rectification ratio is 100 or more and less than 1000. Δ: The rectification ratio is 10 or more and less than 100. X: The rectification ratio is less than 10. [Evaluation of Initial Dark Spot Resistance] ]
Using a constant voltage power supply, DC 5V is applied to each organic EL panel, and the presence or absence of dark spots is visually observed with a loupe (magnification 8 times), and the number of spots of non-light emitting parts in the entire light emission region The initial dark spot resistance was evaluated according to the following criteria.

A: No occurrence of dark spots is observed. O: The number of dark spots is 1 or more and less than 5. Δ: The number of dark spots is 5 or more and less than 20. ×: Dark The number of spots generated is 20 or more. [Evaluation of panel life]
After leaving the sealed side of each of the organic EL panels produced above outside and bending it at an angle of 60 ° for 1000 hours in an environment of 60 ° C. and 90% RH, Apply 5V DC to the EL panel, measure the light emission area with a microscope (MS-804 manufactured by Moritex Corp., lens MP-ZE25-200), perform image analysis using Win Roof (manufactured by Mitani Corporation), and perform initial light emission The ratio of the non-light emitting area (dark spot area) to the area was measured, and the panel life was evaluated according to the following criteria.

A: Ratio of non-light emitting area is less than 0.1% B: Ratio of non-light emitting area is 0.1% or more and less than 1.0% Δ: Ratio of non-light emitting area is 1.0 %more than. Less than 2.0% ×: The ratio of the non-light emitting area is 2.0% or more. Table 1 shows the results obtained as described above.

As is apparent from the results shown in Table 1, after the temporary adhesion, until the heat curing, the production method according to the present invention is performed in the cooling step of 5 ° C. or less specified in the present invention. It can be seen that the organic EL panel has a higher rectification ratio than the comparative example, and is excellent in initial dark spot resistance and panel life.

DESCRIPTION OF SYMBOLS 1 Resin substrate 2 1st electrode 3 Organic EL layer 4 2nd electrode 5 Sealing substrate 6 Adhesive layer P Organic EL panel

Claims

At least a first electrode, an organic compound layer including a light emitting layer, and a substrate on which an organic electroluminescence element having a second electrode is formed. In the manufacturing method of the organic electroluminescent panel to be formed, the sealing material is a thermosetting resin or an ultraviolet curable resin, and the organic electroluminescent panel is formed by bonding a sealing substrate on the substrate via the sealing material. A method for producing an organic electroluminescence panel, which is produced by subjecting a surface to adhesion, followed by a step of cooling to 5 ° C. or lower, and then applying heat or ultraviolet light to the sealing material to cure.
The method for manufacturing an organic electroluminescence panel according to claim 1, wherein the substrate and the sealing substrate are both flexible substrates.
The method for producing an organic electroluminescence panel according to claim 1, wherein the sealing substrate is a moisture-proof film having a metal foil.
The method for manufacturing an organic electroluminescence panel according to any one of claims 1 to 3, wherein the sealing material is an epoxy thermosetting resin.
The substrate is formed by bonding a sealing substrate on the substrate on which the organic electroluminescence element is formed via the sealing material and bonding the surface to each other, and then performing a process of cooling to 5 ° C. or less within 12 hours. The manufacturing method of the organic electroluminescent panel of any one of Claim 1 to 4 characterized by the above-mentioned.
The method for producing an organic electroluminescence panel according to any one of claims 1 to 5, wherein a treatment time in the step of cooling to 5 ° C or lower is 2 hours or more.
The method for producing an organic electroluminescence panel according to any one of claims 1 to 6, wherein a treatment temperature in the step of cooling to 5 ° C or lower is 0 ° C or lower.
An organic electroluminescence panel manufactured using the method for manufacturing an organic electroluminescence panel according to any one of claims 1 to 7.