JP2014103015A - Organic electroluminescent device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent device which is hardly distorted even when used for a long period of time, is excellent in durability, and is stably driven.SOLUTION: An organic electroluminescent device 1 of the present invention has an element substrate 2, an organic electroluminescent element 3 provided on the element substrate 2, and a sealing plate 4 provided on the organic electroluminescent element 3. One of the element substrate 2 and the sealing plate 4 includes a metal foil, and the other of the element substrate 2 and the sealing plate 4 includes a glass plate. The absolute value of a difference between the linear expansion coefficient of the element substrate 2 and the linear expansion coefficient of the sealing plate 4 is 12 ppm/°C or less.

Description

  The present invention relates to an organic electroluminescence device.

Hereinafter, organic electroluminescence is referred to as “organic EL”.
Conventionally, an organic EL device having an element substrate, an organic EL element provided on the element substrate, and a sealing plate provided on the organic EL element is known. The organic EL element includes a first electrode, a second electrode, and an organic layer provided between the two electrodes.
Organic EL devices are typically used in lighting devices, image display devices, and the like.

In recent years, development of flexible devices has been promoted. Under such circumstances, an organic EL device using a flexible synthetic resin plate as the element substrate is known. However, the synthetic resin plate has a low barrier property against moisture, oxygen and the like, and the organic EL element using the synthetic resin plate has a problem of low durability.
In view of such problems, Patent Document 1 discloses using a metal foil as an element substrate of a light emitting element, and Patent Document 2 discloses using a glass plate as an element substrate for a light emitting element. Yes.

However, even when a metal foil or glass plate having excellent barrier properties against water vapor or the like is used as an element substrate, when a synthetic resin plate having low barrier properties is used as a sealing plate, an organic EL element having excellent durability is obtained. Cannot be configured.
Further, even when a material having a high barrier property is used as the sealing plate, the element substrate or the sealing plate can be obtained by heat generated by continuing to use the organic EL device or by storing the organic EL element in a high temperature and high humidity environment. May deform, and as a result, the organic EL device may be distorted. Due to the distortion, the element substrate or the sealing plate is peeled off, and moisture and the like enter the organic EL element, so that the durability of the organic EL device is lowered. Further, the driving life of the organic EL element is reduced due to the distortion.

Patent No. 3942017 (Japanese Patent Laid-Open No. 2003-282258) JP 2008-107510 A

  An object of the present invention is to provide an organic EL device having excellent durability.

  The organic EL device of the present invention includes an element substrate, an organic EL element provided on the element substrate, and a sealing plate provided on the organic EL element. Either one of the stop plates includes a metal foil, the other of the element substrate or the sealing plate includes a glass plate, and the absolute value of the difference between the linear expansion coefficient of the element substrate and the linear expansion coefficient of the sealing plate is , 12 ppm / ° C. or less.

In a preferred organic EL device of the present invention, a synthetic resin layer is provided on at least one surface of the glass plate.
In a preferred organic EL device of the present invention, the element substrate and the sealing plate have flexibility.
In a preferred organic EL device of the present invention, the sealing plate is bonded onto the organic EL element via an adhesive layer.

Even if the organic EL device of the present invention is used for a long time, distortion due to heat hardly occurs.
ADVANTAGE OF THE INVENTION According to this invention, the organic electroluminescent apparatus which is hard to deteriorate locally and was excellent in durability can be provided.

1 is a plan view of an organic EL device according to one embodiment of the present invention. The expanded sectional view cut | disconnected by the II-II line | wire of FIG. The expanded sectional view which cut | disconnected the organic EL apparatus which concerns on other embodiment of this invention in the direction similar to the II-II line | wire of FIG.

The present invention will be described below with reference to the drawings. However, it should be noted that dimensions such as layer thickness and length in each figure are different from actual ones.
Further, in the present specification, there are cases where “first” and “second” are added to the beginning of the term, but this first etc. is added only for distinguishing the terms, and the order thereof. And has no special meaning such as superiority or inferiority. The “planar shape” refers to a shape viewed from the vertical direction with respect to the surface of the element substrate. The notation “PPP to QQQ” means “PPP or more and QQQ or less”.

[Configuration of organic EL device]
1 and 2 show an organic EL device according to one embodiment of the present invention. FIG. 3 shows an organic EL device according to another embodiment of the present invention. The plan view of the organic EL device according to the other embodiment is omitted. When each part which comprises the organic EL device which concerns on the said other embodiment, and each part which comprises the organic EL apparatus which concerns on the said one embodiment are the same contents, of the organic EL apparatus which concerns on other embodiment Description of each part is abbreviate | omitted and the code | symbol of each part of the said one embodiment is used as it is in FIG.
However, the organic EL device of the present invention is not limited to the configuration shown in FIGS.

1 and 2, an organic EL device 1 according to the present invention includes an element substrate 2, an organic EL element 3 provided on the element substrate 2, and a sealing plate 4 that seals the organic EL element 3. Have.
The organic EL element 3 includes a first electrode 31, a second electrode 32, and an organic layer 33 provided between the electrodes 31 and 32.
The sealing plate 4 covers the surface of the organic EL element 3 including the side end face of the organic EL element 3 except for the terminal 311 of the first electrode 31 and the terminal 321 of the second electrode 32. Note that an adhesive layer 5 is provided between the sealing plate 4 and the element substrate 2 in order to fix the sealing plate 4 to the organic EL element 3. The sealing plate 4 is bonded to the element substrate 2 through the adhesive layer 5.

When the element substrate 2 has conductivity, an electrical insulating layer (not shown) is provided between the element substrate 2 and the first electrode 31 in order to prevent an electrical short circuit.
As illustrated in FIG. 3, a barrier layer 6 may be provided between the second electrode 32 and the sealing plate 4 as necessary.

The planar shape of the organic EL device 1 is substantially rectangular. The planar shape of the terminal 311 of the first electrode 31 is strip-shaped and extends along one long side of the substantially rectangular shape, and the planar shape of the terminal 321 of the second electrode 32 is strip-shaped and is substantially rectangular. It extends along the other long side.
However, the terminals 311 and 321 are not limited to the case where they extend along the long side, but may extend along the short side. Further, each of the terminals 311 and 321 is not limited to a belt shape, but may be an arc shape or a spot shape.
Furthermore, the planar shape of the organic EL device 1 is not limited to a substantially rectangular shape, and may be, for example, a square shape or a substantially circular shape.

The first electrode 31 and the first electrode 31 are arranged such that the side edge 311a of the terminal 311 of the first electrode 31 and the side edge 321a of the terminal 321 of the second electrode 32 are located inside the side edges 21a and 22a of the element substrate 2, respectively. Two electrodes 32 are provided.
As shown in FIG. 3, the side edge 311a of the terminal 311 of the first electrode 31 and the side edge 321a of the terminal 321 of the second electrode 32 are aligned with the side edges 21a and 22a of the element substrate 2, respectively. Both electrodes 31 and 32 may be provided.

Either the element substrate 2 or the sealing plate 4 includes a metal foil, and the other of the element substrate or the sealing plate includes a glass plate. That is, when the element substrate 2 is a substrate including a metal foil, the sealing plate 4 is a substrate including a glass plate, and on the other hand, when the element substrate 2 is a substrate including a glass plate, The sealing plate 4 is a substrate including a metal foil. By using a substrate including a metal foil as one of the element substrate 2 and the sealing plate 4, it is possible to effectively prevent water vapor and the like from entering the organic EL element 3, and heat generated from the element 3. Can be diffused to the outside smoothly. With such barrier properties and heat dissipation properties, the driving life of the organic EL device can be extended. In addition, the light from the organic EL element 3 can be radiate | emitted outside by using a glass plate as said any other.
It is preferable that the board | substrate containing the said metal foil and the board | substrate containing a glass plate have flexibility (flexibility). The flexible substrate means, for example, a sheet-like material that is flexible enough to be wound up in a roll shape.

The absolute value of the difference between the linear expansion coefficient of the element substrate 2 and the linear expansion coefficient of the sealing plate 4 needs to be 12 ppm / ° C. or less. The lower limit of the difference between the linear expansion coefficient of the element substrate 2 and the linear expansion coefficient of the sealing plate 4 is zero.
In this specification, the linear expansion coefficient refers to a value measured by a TMA method (thermomechanical analysis method) according to JIS K7197.

The element substrate 2 and the sealing plate 4 are expanded by heat generated when the organic EL device 1 is continuously used or by storing the organic EL element in a high-temperature and high-humidity environment. When the absolute value of the difference in coefficient is 12 ppm / ° C. or less, the distortion of the organic EL device 1 due to the difference in expansion between the element substrate 2 and the sealing plate 4 is extremely reduced.
If the strain of the organic EL device is large, (1) the element substrate or the sealing plate is peeled off from the organic EL element, (2) a crack occurs in the element substrate or the sealing plate, and the inside of the organic EL element Oxygen and moisture enter the surface, and (3) the organic EL element is locally degraded due to distortion of the organic EL element. In such a case, the durability of the organic EL device is reduced, and the product life of the organic EL device is reduced.
In this respect, the organic EL device 1 of the present invention has excellent durability and a long product life because the distortion due to the expansion difference between the element substrate 2 and the sealing plate 4 is extremely small as described above. Furthermore, in the organic EL device 1 of the present invention, it is possible to prevent a decrease in the driving life of the organic EL element due to local deterioration of the organic EL element.

Since the organic layer 33 is formed of a light emitting material, the organic EL device 1 of the present invention can be used as a light emitting panel such as a lighting device or an image display device.
Hereinafter, taking the organic EL device 1 that emits light as an example, the forming material thereof will be described.

(Organic EL device)
The first electrode of the organic EL element is, for example, an anode.
The material for forming the first electrode (anode) is not particularly limited. For example, indium tin oxide (ITO); indium tin oxide containing silicon oxide (ITSO); aluminum; gold; platinum; nickel; tungsten; Alloy; and the like. When forming a bottom emission type light emitter, a transparent first electrode is used. The thickness of the first electrode is not particularly limited, and is usually 0.01 μm to 1.0 μm.
In the present specification, examples of the transparent index include a total light transmittance of 70% or more, preferably 80% or more. However, the total light transmittance means a value measured by a measurement method according to JIS K 7105 (plastic optical property test method).

The organic layer of the organic EL element is a laminate composed of at least two layers. As the structure of the organic layer, for example, (A) a structure composed of three layers, a hole transport layer, a light emitting layer, and an electron transport layer, and (B) composed of two layers, a hole transport layer and a light emitting layer. Examples thereof include a structure, (C) a structure composed of two layers of a light emitting layer and an electron transport layer.
In the organic layer (B), the light emitting layer also serves as the electron transport layer. In the organic layer (C), the light emitting layer also serves as the hole transport layer.
The organic layer used in the present invention may have any of the structures (A) to (C).
Hereinafter, the organic layer having the structure (A) will be briefly described.

The hole transport layer is provided on the surface of the first electrode. For example, the hole injection layer may be provided on the surface of the first electrode, and the hole transport layer may be provided on the surface of the hole injection layer.
The material for forming the hole transport layer is not particularly limited as long as it is a material having a hole transport function, and a known material can be used.
The thickness of the hole transport layer is not particularly limited, and is preferably 1 nm to 500 nm from the viewpoint of lowering the driving voltage.

The light emitting layer is provided on the surface of the hole transport layer.
The material for forming the light emitting layer is not particularly limited as long as it is a light emitting material, and a known material can be used.
The thickness of a light emitting layer is not specifically limited, For example, 2 nm-500 nm are preferable.

The electron transport layer is provided on the surface of the light emitting layer. For example, the electron injection layer may be provided on the surface of the electron transport layer, and the second electrode may be provided on the surface of the electron injection layer.
The material for forming the electron transport layer is not particularly limited as long as it is a material having an electron transport function, and a known material can be used.
The thickness of the electron transport layer is not particularly limited, and is preferably 1 nm to 500 nm from the viewpoint of lowering the driving voltage.

The second electrode of the organic EL element is, for example, a cathode.
The material for forming the second electrode is not particularly limited, and a transparent second electrode is used when forming a top emission type light emitter. As a material for forming the transparent and conductive second electrode, indium tin oxide (ITO); indium tin oxide containing silicon oxide (ITSO); zinc oxide to which a conductive metal such as aluminum is added (ZnO: Al) ); Magnesium-silver alloy and the like. The thickness of the second electrode is not particularly limited, and is usually 0.01 μm to 1.0 μm.

  The barrier layer is provided to protect the organic EL element and prevent intrusion of moisture and oxygen. The material for forming the barrier layer is not particularly limited, and examples thereof include a metal oxide film, an oxynitride film, a nitride film, and an oxycarbonitride film. The thickness of the barrier layer is not particularly limited and is, for example, 50 nm to 50 μm.

(Element board)
The element substrate is provided to support the organic EL element and prevent moisture, oxygen, and the like from entering the organic EL element.
As the element substrate, either a substrate including a metal foil or a substrate including a glass plate is used. The board | substrate containing the said metal foil and the board | substrate containing a glass plate are explained in full detail below.
As described above, the element substrate satisfying the formula: 0 ≦ | linear expansion coefficient of element substrate−linear expansion coefficient of sealing plate | ≦ 12 ppm / ° C. is used.
Preferably, 0 ≦ | linear expansion coefficient of the element substrate−linear expansion coefficient of the sealing plate | ≦ 10 ppm / ° C., more preferably 0 ≦ | linear expansion coefficient of the element substrate−linear expansion coefficient of the sealing plate | ≦ 7 ppm / ° C.

As the element substrate, for example, a flexible substrate can be used.
The element substrate may be either transparent or opaque. When forming a bottom emission type organic EL device, a transparent substrate (that is, a substrate including a glass plate) is used as an element substrate.

(Sealing plate)
The sealing plate is provided to protect the organic EL element and prevent moisture, oxygen, and the like from entering the organic EL element.
As the sealing plate, either the substrate including the metal foil or the substrate including the glass plate is used. The board | substrate containing the said metal foil and the board | substrate containing a glass plate are explained in full detail below.
As the sealing plate, for example, a flexible substrate can be used.
The sealing plate may be either transparent or opaque. In the case of forming a top emission type organic EL device, a transparent substrate (that is, a substrate including a glass plate) is used as a sealing plate.

(Substrate containing metal foil)
The board | substrate containing metal foil is a sheet-like thing, Preferably, it is a sheet-like thing which has flexibility.
As a board | substrate containing metal foil, the laminated body etc. with which the insulating layer was laminated | stacked only on metal foil or one side or both sides of metal foil are mentioned.
Examples of the metal foil include stainless steel foil, aluminum foil, copper foil, silver foil, gold foil, brass foil, nickel foil, titanium foil, tin foil, copper alloy foil, and nickel alloy foil.
These foils can be obtained by methods such as metal rolling.

  Although the thickness of the said metal foil is not specifically limited, For example, they are 10 micrometers-150 micrometers, Preferably they are 10 micrometers-100 micrometers. If the thickness of the metal foil is smaller than the above, it is not possible to sufficiently prevent the intrusion of moisture and oxygen. On the other hand, if the thickness of the metal foil is larger than the above, the metal foil will not have flexibility.

The insulating layer is provided to prevent the electrode of the organic EL element from being short-circuited.
Examples of the material for forming the insulating layer include metal oxides such as silicon oxide, zinc oxide, aluminum oxide, titanium oxide, and copper oxide; metal nitrides such as silicon nitride and aluminum nitride; polyester, polystyrene, polycarbonate, polyethersulfone, And synthetic resins such as polyarylate, polyimide, polycycloolefin, and norbornene resin. These can be used alone or in combination of two or more.
The linear expansion coefficient of the insulating layer is not particularly limited, but is preferably equivalent to the metal foil.
The thickness of the insulating layer is not particularly limited. When the insulating layer is formed of an inorganic material, the thickness is 10 nm to 1000 nm. When the insulating layer is formed of a synthetic resin material, the thickness is 1 μm to 50 μm.

The substrate including the metal foil preferably has a moisture permeability of 0.01 mg / m ² · day or less. The oxygen permeability of the substrate including the metal foil is preferably 0.01 cc / m ² · day · atm or less. By using a substrate having such a low moisture permeability and oxygen permeability, it is possible to effectively prevent moisture and oxygen from entering the organic EL element.
The moisture permeability refers to a value measured by a measuring method according to JIS K 7129-1992. The oxygen permeability refers to a value measured by a measuring method according to JIS K 7126-1987.
Although the linear expansion coefficient of the board | substrate containing the said metal foil is not specifically limited, For example, it is 25 ppm / degrees C or less, Preferably it is 20 ppm / degrees C or less. The lower limit of the linear expansion coefficient of the substrate including the metal foil is theoretically zero. In practice, however, it is difficult to obtain a metal foil having a linear expansion coefficient of zero. For this reason, the linear expansion coefficient of the board | substrate containing the said metal foil is 3 ppm / degrees C or more, Preferably it is 5 ppm / degrees C or more.

(Substrate including glass plate)
The substrate including the glass plate is a transparent sheet-like material, and preferably a flexible sheet-like material.
As a board | substrate containing a glass plate, the laminated body by which the resin layer was laminated | stacked only on the glass plate or the one surface or both surfaces of the glass plate is mentioned.

The glass plate is usually formed from inorganic glass. Examples of the inorganic glass include soda lime glass, borate glass, aluminosilicate glass, and quartz glass according to the classification according to the composition. According to the classification according to the alkali component, alkali-free glass, low alkali glass, and the like. Is mentioned. Content of the alkali metal component in the said glass becomes like this. Preferably it is 15 mass% or less, More preferably, it is 10 mass% or less.
Although the thickness of the said glass plate is not specifically limited, For example, they are 10 micrometers-100 micrometers, Preferably they are 20 micrometers-70 micrometers, More preferably, they are 25 micrometers-55 micrometers.

  The method for forming the inorganic glass is not particularly limited, and any appropriate method can be adopted. For example, the inorganic glass is obtained by melting a mixture containing a main raw material such as silica or alumina, an antifoaming agent such as sodium nitrate or antimony oxide, and a reducing agent such as carbon at a temperature of 1400 ° C. to 1600 ° C. It can be obtained by cooling into a shape.

  As the inorganic glass, a commercially available product may be used as it is, or a commercially available inorganic glass may be polished to have a desired thickness. Examples of commercially available inorganic glasses include “7059”, “1737” or “EAGLE 2000” manufactured by Corning, “AN100” manufactured by Asahi Glass, “NA-35” manufactured by NH Techno Glass, and “OA-” manufactured by Nippon Electric Glass. 10 "and the like.

  The material for forming the resin layer is not particularly limited as long as it is transparent, and any appropriate resin can be used. For example, examples of the material for forming the resin layer include a thermosetting or ultraviolet curable resin such as a polyethersulfone resin, a polycarbonate resin, an epoxy resin, an acrylic resin, and a polyolefin resin. In particular, since a resin layer excellent in surface smoothness can be formed, it is preferable to use a resin composition containing an epoxy resin as a main component as a material for forming the resin layer.

The epoxy resin is not particularly limited as long as it is a polymer having an epoxy group in the molecule. Examples of the epoxy resin include bisphenol types such as bisphenol A type, bisphenol F type, bisphenol S type, and water additives thereof; novolak types such as phenol novolac type and cresol novolac type; triglycidyl isocyanurate type; Nitrogen-containing ring type such as hydantoin type; alicyclic type; aliphatic type; aromatic type such as naphthalene type and biphenyl type; glycidyl type such as glycidyl ether type, glycidyl amine type and glycidyl ester type; dicyclopentadiene type, etc. Dicyclo type; ester type; ether ester type; modified type thereof; and the like. These epoxy resins can be used alone or in combination of two or more.
Preferably, the resin layer is a cured layer of an epoxy-based prepolymer represented by general formulas (I), (II), (III) and (IV) disclosed in JP-A-2008-107510.
The method disclosed in Japanese Patent Application Laid-Open No. 2008-107510 can also be adopted as a method of forming the resin layer on one or both surfaces of the glass plate.

  Although the thickness of the said resin layer is not specifically limited, For example, they are 1 micrometer-100 micrometers, More preferably, they are 1 micrometer-50 micrometers. When the resin layers are provided on both sides of the glass plate, the thickness of each resin layer may be the same or different, but preferably the thickness of each resin layer is the same. Moreover, each resin layer may be comprised with the same material, or may be comprised with a different material. Preferably, each resin layer is made of the same material.

The moisture permeability of the substrate including the glass plate is preferably 0.01 mg / m ² · day or less. The substrate including the glass plate preferably has an oxygen permeability of 0.01 cc / m ² · day · atm or less. By using a substrate having such a low moisture permeability and oxygen permeability, it is possible to effectively prevent moisture and oxygen from entering the organic EL element.
The moisture permeability refers to a value measured by a measuring method according to JIS K 7129-1992. The oxygen permeability refers to a value measured by a measuring method according to JIS K 7126-1987.
Although the linear expansion coefficient of the board | substrate containing the said glass plate is not specifically limited, For example, it is 15 ppm / degrees C or less, Preferably it is 12 ppm / degrees C or less. The lower limit of the linear expansion coefficient of the substrate including the glass plate is theoretically zero. In practice, however, it is difficult to obtain a glass plate having a linear expansion coefficient of zero. For this reason, the linear expansion coefficient of the board | substrate containing the said glass plate is 1 ppm / degrees C or more, Preferably it is 2 ppm / degrees C or more.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples.

(Substrate used)
(A) Glass-containing substrate A
A resin composition mainly composed of an epoxy resin represented by the following chemical formula (formula (1): formula (2) = 50: 50 (weight ratio)) is sandwiched between release films subjected to silicone treatment, A laminated body including an epoxy resin layer having a thickness of 30 μm was obtained by passing between metal rolls fixed at intervals of 50 μm. Next, using an ultraviolet irradiation device (conveyor speed: 2.5 m / min), ultraviolet rays are irradiated from one side of the laminate (irradiation energy: 250 mJ / cm ² ), and the epoxy resin layer is semi-cured. To form a semi-cured layer. Next, one release film is removed, and a laminator is used to apply the semi-cured layer of the laminate to the surface of one side of inorganic glass (Matsunami Glass Industrial Co., Ltd. borosilicate glass, thickness: 30 μm). Sticked. The same operation was performed on the other side of the inorganic glass to attach the semi-cured layer. Subsequently, after removing the remaining release film, the film was irradiated again with ultraviolet rays (irradiation energy: 5000 mJ / cm ² or more). Thereafter, heat treatment was performed at 130 ° C. or higher for 10 minutes or longer to completely cure the semi-cured layers on both sides of the inorganic glass. Thus, a glass-containing substrate A having a laminated structure of 30 μm resin layer / 30 μm inorganic glass / 30 μm resin layer was obtained.

(B) Glass-containing substrate B
10 μm resin layer / 30 μm inorganic glass / 10 μm resin layer in the same manner as the glass-containing substrate A, except that the resin layers formed on both sides of the inorganic glass of the glass-containing substrate A were changed to 10 μm. A glass-containing substrate B having a multilayer structure was obtained.

(C) Metal-containing substrate C
As the metal-containing substrate C, one obtained by laminating an insulating layer having a thickness of 3 μm on a SUS444 foil having a thickness of 50 μm was used. The insulating layer was coated with a wire bar using an acrylic resin (trade name “JEM-477” manufactured by JSR Corporation), and laminated on one surface of the stainless steel foil.
(D) Metal-containing substrate D
As the metal-containing substrate D, one obtained by laminating an insulating layer having a thickness of 3 μm on a SUS304 foil having a thickness of 50 μm was used. The insulating layer was coated with a wire bar using an acrylic resin (trade name “JEM-477” manufactured by JSR Corporation), and laminated on one surface of the stainless steel foil.
(E) Metal-containing substrate E
As the metal-containing board | substrate E, what laminated | stacked the insulating layer of thickness 3 micrometers on the copper foil of thickness 50 micrometers was used. The insulating layer was coated with a wire bar using an acrylic resin (trade name “JEM-477” manufactured by JSR Corporation) and laminated on one surface of the copper foil.
(F) Metal-containing substrate F
As the metal-containing substrate F, a substrate in which an insulating layer having a thickness of 3 μm was laminated on an aluminum foil having a thickness of 50 μm was used. The insulating layer was coated with a wire bar using an acrylic resin (trade name “JEM-477” manufactured by JSR Corporation) and laminated on one surface of the aluminum foil.
Each thickness was measured using an Anritsu digital micrometer “KC-351C type”.

(Linear expansion coefficient of substrate)
About the said glass containing board | substrate A thru | or B and the metal containing board | substrates C thru | or F, the linear expansion coefficient was measured with the following measuring method, respectively. The results are shown in Table 1.
The linear expansion coefficient was measured by measuring the TMA value (μm) at 30 ° C. to 150 ° C. using TMA / SS150C (manufactured by Seiko Instruments Inc.), and calculating the average linear expansion coefficient.

[Example 1]
A metal-containing substrate C was used as the element substrate, and a glass-containing substrate A was used as the sealing plate.
Then, a first electrode was formed by depositing aluminum having a thickness of 100 nm on the insulating layer of the element substrate by a vacuum deposition method. On the first electrode, 1,4,5,8,9,12-hexaazatriphenylenehexacarbonitrile (abbreviation: HAT-CN) having a thickness of 10 nm is formed as a hole injection layer, and the hole injection is performed. On the layer, N, N′-bis (naphthalen-1-yl) -N, N′-bis (phenyl) -benzidine (abbreviation: NPB) having a thickness of 50 nm was formed as a hole transporting layer. On the hole transport layer, tris (8-quinolinolato) aluminum (abbreviation: Alq) having a thickness of 45 nm was formed as a light-emitting layer also serving as an electron transport layer, and a thickness of 0. A 5 nm LiF film was formed.
Further, Mg / Ag (co-evaporation) having a thickness of 5/15 nm was formed as a second electrode on the electron injection layer by vacuum deposition. In this way, an organic EL element was formed on the element substrate.
Next, a thermosetting adhesive mainly composed of an epoxy resin is applied to the back surface of the sealing plate (applied so that the layer thickness of the adhesive at the time of curing is approximately 10 μm), and the organic EL element The organic EL element was sealed with a sealing plate by curing the adhesive by overlapping and heating.
Thus, a top emission type organic EL device (light emitting device) was produced.

[Example 2]
A top emission type organic EL device was produced in the same manner as in Example 1 except that the metal-containing substrate D was used as the element substrate.

[Example 3]
A top emission type organic EL device was produced in the same manner as in Example 1 except that the metal-containing substrate E was used as the element substrate.

[Example 4]
A top emission type organic EL device was produced in the same manner as in Example 1 except that the metal-containing substrate C was used as the element substrate and the glass-containing substrate B was used as the sealing plate.

[Example 5]
A top emission type organic EL device was produced in the same manner as in Example 1 except that the metal-containing substrate D was used as the element substrate and the glass-containing substrate B was used as the sealing plate.

[Example 6]
A top emission type organic EL device was produced in the same manner as in Example 1 except that the metal-containing substrate E was used as the element substrate and the glass-containing substrate B was used as the sealing plate.

[Example 7]
A glass-containing substrate A was used as the element substrate, and a metal-containing substrate C was used as the sealing plate.
Then, a first electrode was formed on the element substrate by depositing ITO having a thickness of 100 nm by a sputtering method. On the first electrode, 1,4,5,8,9,12-hexaazatriphenylenehexacarbonitrile (abbreviation: HAT-CN) having a thickness of 10 nm is formed as a hole injection layer, and the hole injection is performed. On the layer, N, N′-bis (naphthalen-1-yl) -N, N′-bis (phenyl) -benzidine (abbreviation: NPB) having a thickness of 50 nm was formed as a hole transporting layer. On the hole transport layer, tris (8-quinolinolato) aluminum (abbreviation: Alq) having a thickness of 45 nm was formed as a light-emitting layer also serving as an electron transport layer, and a thickness of 0. A 5 nm LiF film was formed.
Further, on the electron injection layer, aluminum having a thickness of 100 nm was formed as a second electrode by vacuum deposition. In this way, an organic EL element was formed on the element substrate.
Next, a thermosetting adhesive mainly composed of an epoxy resin is applied to the back surface of the sealing plate (applied so that the layer thickness of the adhesive at the time of curing is approximately 10 μm), and the organic EL element The organic EL element was sealed with a sealing plate by curing the adhesive by overlapping and heating.
Thus, a bottom emission type organic EL device (light emitting device) was produced.

[Example 8]
A bottom emission type organic EL device was produced in the same manner as in Example 7 except that the metal-containing substrate D was used as the sealing plate.

[Example 9]
A bottom emission type organic EL device was produced in the same manner as in Example 7 except that the metal-containing substrate E was used as the sealing plate.

[Example 10]
A bottom emission type organic EL device was produced in the same manner as in Example 7 except that the glass-containing substrate B was used as the element substrate.

[Example 11]
A bottom emission type organic EL device was produced in the same manner as in Example 7 except that the metal-containing substrate D was used as the sealing plate and the glass-containing substrate B was used as the element substrate.

[Example 12]
A bottom emission type organic EL device was produced in the same manner as in Example 7 except that the metal-containing substrate E was used as the sealing plate and the glass-containing substrate B was used as the element substrate.

[Comparative Example 1]
A top emission type organic EL device was produced in the same manner as in Example 1 except that the metal-containing substrate F was used as the element substrate.

[Comparative Example 2]
A top emission type organic EL device was produced in the same manner as in Example 4 except that the metal-containing substrate F was used as the element substrate.

[Comparative Example 3]
A bottom emission type organic EL device was produced in the same manner as in Example 7 except that the metal-containing substrate F was used as the sealing plate.

[Comparative Example 4]
A bottom emission type organic EL device (light emitting device) was produced in the same manner as in Example 10 except that the metal-containing substrate F was used as the sealing plate.

[Measurement of change in luminance retention and emission area]
Each of the organic EL devices of Examples 1 to 12 and Comparative Examples 1 to 4 was continuously driven at a constant current of 30 mA / cm ² , and the initial luminance and the luminance after 200 hours were measured. The luminance retention (%) was calculated by substituting these measured values into the following equation. The results are shown in Table 2.
Luminance retention ratio (%) = luminance after 200 hours of light emission / initial luminance The change in the light emission area is the same for each of the organic EL devices of Examples 1 to 12 and Comparative Examples 1 to 4 at a constant temperature of 60 ° C. and 90% RH. It was stored in a constant humidity room in a non-lighted state. At the initial stage of storage and after 200 hours, the organic EL device was caused to emit light, and the light emission area was measured by microscopic observation. The microscope observation and the measurement of the light emission area were performed using a digital microscope (product name “VHX-1000”) manufactured by Keyence Corporation. The luminance retention (%) was calculated by substituting these measured values into the following equation. The results are shown in Table 2.
Change in light emission area (%) = light emission area after 200 hours of light emission / initial light emission area

[Evaluation]
From the comparison between Examples 1 to 12 and Comparative Examples 1 to 4, the absolute value of the difference between the linear expansion coefficient of the element substrate and the linear expansion coefficient of the sealing plate is 12 ppm / ° C. or less (preferably 8 ppm / ° C. or less). In some cases, it can be seen that an organic EL device having a high luminance retention rate and a small reduction in light emitting area can be configured.
As described above, the main reason why the product life of the organic EL device is prolonged is that the element substrate and the sealing plate are hardly peeled or cracked by heat generated during the driving of the device, and the moisture and oxygen barrier properties of the element substrate and the sealing plate are not easily generated. Is presumed to be good and the organic EL element is not locally degraded.

  The organic EL device of the present invention can be used, for example, as an illumination device, an image display device, or the like.

  DESCRIPTION OF SYMBOLS 1 ... Organic EL apparatus, 2 ... Element substrate, 3 ... Organic EL element, 31 ... 1st electrode, 32 ... 2nd electrode, 33 ... Organic layer, 4 ... Sealing plate, 5 ... Adhesion layer

Claims (4)

An element substrate;
An organic electroluminescence element provided on the element substrate;
A sealing plate provided on the organic electroluminescence element,
Either the element substrate or the sealing plate includes a metal foil, and the other of the element substrate or the sealing plate includes a glass plate,
An organic electroluminescence device, wherein an absolute value of a difference between a linear expansion coefficient of the element substrate and a linear expansion coefficient of the sealing plate is 12 ppm / ° C or less.   The organic electroluminescent device according to claim 1, wherein a synthetic resin layer is provided on at least one surface of the glass plate.   The organic electroluminescence device according to claim 1, wherein the element substrate and the sealing plate have flexibility.   The organic electroluminescent device according to any one of claims 1 to 3, wherein the sealing plate is bonded onto the organic electroluminescent element via an adhesive layer.

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