JPH11224771A - Organic electroluminescence element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescence element in which the attack by oxygen and water on the organic eloectroluminescence element from the outside is prevented, deterioration with the lapse of time such as the growth of the dark spot and reduction of the brightness is less, and the service life is improved. SOLUTION: An organic electroluminescence element is provided with a lamination structural body comprising an electron injection electrode 6, an organic thin film layer 3 and a hole injection electrode 2 on a transparent or translucent substrate 1, and the outer surface of the lamination structural body is protected by a shield member 7. At least a part of the substrate 1 and the shield member 7 are adhered to each other with an adhesive layer 8 of a photo-curing epoxy resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device which is an electric light emitting device used for a backlight of a liquid crystal display, a light source for a display, a display and an optical communication, and more particularly to an organic electroluminescent device. The present invention relates to an organic electroluminescence device having an optimized sealing structure for improving reliability.

[0002]

2. Description of the Related Art Electroluminescent devices (hereinafter referred to as "electroluminescent devices")
An “EL element” is a light-emitting device that uses a phenomenon called electroluminescence or electroluminescence of a solid fluorescent substance, and an inorganic EL element using an inorganic material as a light emitter has been put to practical use, and Applications to display backlights, flat displays, etc. are being developed. However, the inorganic EL element requires an alternating current and a high voltage of 100 V or more to cause the element to emit light, and it is difficult to emit blue light, and it is difficult to achieve full color by three primary colors of R, G, and B light. There are disadvantages.

[0003] On the other hand, research on EL devices using organic materials has been conducted for a long time. However, since the efficiency is extremely low, only low luminance can be obtained and full-scale research for practical use has not been achieved. However, in 1987, Kodak's C.I.
W. An organic EL device having a structure proposed by Tang et al., That is, a function-separated stacked structure in which an organic substance is divided into a hole transport layer and a light-emitting layer is 1000 cd / m ² despite a low voltage of 10 V or less. The above high-luminance light emission was realized (CW Tang and SAV)
anslyke: Appl. Phys. Lett, 51
(1987) 913). As a result, organic EL has suddenly attracted attention, and in recent years, studies on a stacked organic EL element having a similar configuration have been actively conducted.

Here, the configuration of a conventional organic electroluminescent element will be briefly described with reference to FIG.

FIG. 3 is a structural view of a conventional organic electroluminescent device. In FIG. 3, a hole injection electrode 11 made of a transparent electrode film such as ITO formed on a transparent glass substrate 10 by a sputtering method or a vacuum evaporation method is laminated as an anode.
On top of TPD (N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-diphenyl-4,
A hole transport layer 12 such as 4′-diamine) is laminated. Then, Alq ₃ (8
-Hydroxyquinoline Aluminum
m) and the like are formed by a vacuum evaporation method, and an electron injection electrode 14 is stacked on the light emitting layer 13 as a cathode. The electron injection electrode 14 is mainly made of a metal film having a low work function, such as AlLi or MgAg.

[0006] By applying a positive DC voltage to the hole injection electrode 11 and a negative DC voltage to the electron injection electrode 14 to the organic EL device having this configuration, recombination in the light emitting layer, thereby generation of excitons, and finally Light emission is caused by the transition from the excited state to the ground state. In an organic electroluminescent element having such a light emitting principle, an arbitrary light emitting wavelength can be easily controlled by changing a light emitting material and a layer structure, and therefore, application to various light emitting devices and full color displays is expected.

[0007] As described above, the organic EL element directly emits light from the light emitting layer 13 through the electron injection electrode 14 or through the electron transport layer.
Light is emitted by recombination of electrons injected into the light emitting layer 13 and holes injected into the light emitting layer 13 directly from the hole injection electrode 11 or through the hole transport layer 12. In order to improve the light emission characteristics of an organic electroluminescence device based on such a light emission mechanism, mainly, 1) improvement of an organic film such as a light emitting layer 13, a hole transport layer 12, and 2) a hole injection electrode 11 and electron injection. The electrode 14 needs to be improved. Of these, the improvement of the cathode material of the electron injection electrode 14 in (2) is intended to make it easier for electrons to enter the light emitting layer. Therefore, the barrier between the electron injection electrode 14 and the light emitting layer 13 must be reduced. Therefore, the cathode material of the electron injection electrode 14 needs to have a small work function and a high electric conductivity.
For example, MgAg (U.S. Pat. No. 4,885,21)
No. 1) and alloys such as AlLi (JP-A-5-121172) are generally used.

[0008] These alloys are very active and chemically unstable. For this reason, the cathode material is corroded and oxidized by moisture and oxygen from the outside, so that a non-light-emitting portion called a dark spot existing on the light-emitting surface is remarkably grown, and the deterioration over time such as a decrease in luminance is easily caused. Organic solids such as the light emitting layer 13 and the hole transport layer 12 used in the organic electroluminescence element are generally weak to moisture and oxygen, and similarly cause dark spot growth and luminance reduction. Therefore, a practical organic electroluminescence element and a device using the same must seal the element for the purpose of preventing moisture and oxygen from entering an organic material and an electrode material, and improve reliability.

Various proposals have been made on a method of sealing an organic electroluminescence element. For example, a method practically used in an inorganic electroluminescence element, that is, a method in which a glass plate is provided outside a back electrode and silicone oil is sealed between the back electrode and the glass plate, and Japanese Patent Application Laid-Open No. 5-89959. As disclosed, a method of providing a protective film made of an insulating inorganic compound on an element and providing a shield layer made of an electrically insulating glass or an electrically insulating airtight fluid on the outside thereof, and Japanese Patent Application Laid-Open No. 7-212455. As described above, there is a method of forming a protective film made of a water-absorbing substance having a water absorption of 1% or more and a moisture-proof substance having an absorption of 0.1% or less.

[0010]

As described above, various proposals have been made for a method of sealing an organic electroluminescence element, but no effective sealing method has been developed yet. This is because conventional sealing materials and sealing methods cannot completely prevent moisture and oxygen. For example, the epoxy resin used for bonding the cover glass and the substrate in the above-mentioned Japanese Patent Application Laid-Open No. 5-89959 is generally 3 to 5 (g / m ² · 24 h / mm), and the polyimide resin is 2 (g / m 2). there are ² · 24h / mm) about water vapor permeability. For this reason, it is not possible to completely suppress the entry of moisture from the bonded portion, and as a result, dark spots are grown. Further, as described in Japanese Patent Application Laid-Open
In Japanese Patent No. 11455, both the hygroscopic substance and the moisture-proof substance are prepared by a vapor deposition method, but it is difficult to form these polymer films without defects, and therefore, the growth of dark spots is completely suppressed. It is impossible.

In the method of sealing using a thermosetting epoxy resin, the organic electroluminescent element may be deteriorated when exposed to a high temperature.
Since the temperature is the limit, the curing is insufficient, a high adhesive strength cannot be obtained, and the penetration of moisture from the interface between the resin and the substrate increases. In addition, radically curable acrylate resins, which are the most common photocurable resins, have a problem of poor moisture resistance.

Furthermore, Japanese Patent Application Laid-Open No. 5-182759 proposes a sealing method including a photocurable resin and a substrate having a low permeability.
In a hot and humid environment such as% RH, it is impossible to completely suppress the entry of moisture. This is because, under high temperature and high humidity, water penetrates through the interface between the resin and the substrate due to insufficient adhesion of the photocurable resin, in addition to the penetration of moisture through the photocurable resin.

In order to solve the above-mentioned problems, the present invention uses a low-moisture-permeable, highly-adhesive, photo-curable epoxy resin for bonding the substrate and the shielding material, so that oxygen from the outside to the organic EL element can be prevented. An object of the present invention is to provide an organic electroluminescent element that prevents an attack by moisture and has a long life with little change over time such as growth of a dark spot and a decrease in luminance.

[0014]

According to the present invention, there is provided a laminated structure comprising an electron injection electrode, an organic thin film and a hole injection electrode on a transparent or translucent substrate, and the outer surface of the laminated structure is shielded. An organic electroluminescent element protected by a material, wherein the transparent or translucent substrate and at least a part of the shielding material are bonded with a photocurable epoxy resin.

According to the invention, the growth of dark spots,
A highly reliable organic electroluminescent device with little change over time such as a decrease in luminance can be obtained.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 is provided with a laminated structure comprising an electron injection electrode, an organic thin film and a hole injection electrode on a transparent or translucent substrate. An organic electroluminescent device having a surface protected by a shield material, wherein the transparent or translucent substrate and at least a part of the shield material are bonded by a photo-curable epoxy resin.

In the present invention, the photocurable epoxy resin is more preferably (A) an alicyclic epoxy resin having two or more epoxy groups in one molecule, and (B) one in one molecule.
Epoxy resin having two or more aromatic rings, (C) a compound having two or more hydroxyl groups in one molecule, (D) an alkoxysilyl compound having a functional group capable of reacting with the epoxy resin in one molecule, (E) It is made of a resin composition containing a photocationic curing initiator as an essential component, and it is possible to block moisture and oxygen from the outside to some extent. A decrease with time can be suppressed.

An alicyclic epoxy resin having two or more epoxy groups in one molecule is characterized in that it has good reactivity in a cationically cured system because ring strain is generated in the epoxy group in the molecule. . Therefore, when an alicyclic epoxy resin having two or more epoxy groups in one molecule is used for bonding the substrate and the shield material, the curing is completed in a short time, and the working efficiency is improved. However, when only an alicyclic epoxy resin having two or more epoxy groups in one molecule and a photocationic initiator are used, the moisture permeability increases and the cured product becomes brittle. Furthermore, the adhesiveness is low, so that moisture and oxygen from the outside cannot be cut off, the growth of dark spots in the light emitting layer cannot be prevented, and the decrease in emission luminance over time cannot be suppressed. This is because the alicyclic epoxy resin having two or more epoxy groups in one molecule has a relatively polar functional group and has few water-repellent substituents, so the resin itself has high hygroscopicity. Because it becomes.

Therefore, the present inventors have proposed an alicyclic epoxy resin having two or more epoxy groups in one molecule and an epoxy resin having high water repellency (B) having one or more aromatic rings in one molecule; By combining (E) a photocationic curing initiator and (C) a compound having two or more hydroxyl groups in one molecule, more preferably a compound which is a polyhydric alcohol, toughness is imparted and a dark spot is further provided. Have found that growth can be prevented. further,
(D) By using an alkoxysilyl compound having a functional group capable of reacting with an epoxy resin in one molecule as an essential component, the adhesive strength is improved, and it becomes possible to block external moisture and oxygen to some extent.

The alicyclic epoxy resin (A) having two or more epoxy groups in one molecule, which is an essential component of the photocurable epoxy resin, has an epoxy equivalent of 100 or more and 2,000 or more.
It is more preferred that: Epoxy equivalent is 100
If it is less than the above, there is a possibility that the crosslinked density of the cured resin increases and the resin becomes brittle. If the epoxy equivalent is 2,000 or more, the curability will be poor, and there may be a problem that the tack does not disappear even if ultraviolet light is irradiated for a long time during curing.

1 which is an essential component of the photocurable epoxy resin
In an epoxy resin having one or more aromatic rings in a molecule, the molecule itself has water repellency and low moisture permeability due to the presence of the aromatic ring in the molecule. Examples of such an epoxy resin having one or more aromatic rings in one molecule include bisphenol A
Type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin such as "YX4000" manufactured by Yuka Shell Epoxy Co., Ltd., phenol novolak type epoxy resin, cresol novolak type epoxy resin, dicyclopentadiene Modified phenol novolak type epoxy resin,
Examples thereof include an epoxy-modified compound of a co-condensation resin of a naphthol and a carbonyl group-containing compound. Further, the epoxy resin having one or more aromatic rings in one molecule is more preferably a bisphenol-type epoxy resin, a biphenyl-type epoxy resin, a novolak-type epoxy resin, or a substituted phenol-type epoxy resin. In this case, the content of the aromatic ring unit in the molecule is increased, the water repellency is higher, the waterproofness of the photocurable epoxy resin is improved, moisture and oxygen from outside are blocked, and dark spots in the light emitting layer are reduced. It has an effect that growth can be prevented and a decrease in emission luminance over time can be suppressed.

1 which is an essential component of the photocurable epoxy resin
The compound having two or more hydroxyl groups in the molecule is more preferably a polyhydric alcohol. Polyhydric alcohols have good reactivity with epoxy resins and have the effect of imparting curing acceleration properties and flexibility to photocurable epoxy resins. More preferably, the polyhydric alcohol added to the epoxy photocationically curable resin has a hydroxyl equivalent of 15,000 or less. If the hydroxyl equivalent exceeds 15,000, the curability will decrease,
Unreacted materials may remain in the cured product. Further, when the hydroxyl equivalent exceeds 15,000, the workability of the photocurable epoxy resin may be deteriorated.

Representative examples of such compounds having two or more hydroxyl groups in one molecule include polyhydric alcohols such as hexanediol, neopentyl glycol, trimethylolpropane and glycerin, and polyhydric alcohols such as polyethylene glycol and polypropylene glycol. Examples thereof include alkylene glycols and hydroxyl-modified polybutadiene.

Further, an alkoxysilyl compound having a functional group capable of reacting with an epoxy resin in one molecule is an essential component of an adhesive from the viewpoint of imparting adhesiveness to a photocurable resin. An alkoxysilyl compound having no functional group capable of reacting with an epoxy resin is not preferable because it remains as an unreacted substance in a cured product and bleeds may occur when a moisture resistance test is performed. Further, since the curing system of the photo-curable epoxy resin is a cationic system, the functional group which reacts quickly with the epoxy resin is more preferably an alicyclic epoxy group. As such an example, a product name “A-18” manufactured by Nippon Unicar Co., Ltd.
6 "and the like.

Examples of the photocationic curing initiator, which is an essential component of the photocurable epoxy resin, include diazonium salts and sulfonium salts. The diazonium salt has a high activity against light, but generates nitrogen during photodecomposition, so that there is a possibility that air bubbles may be involved in the cured product, and the photocationic curing initiator is more preferably a sulfonium salt. Further, the sulfonium salt preferably has a hydroxyalkyl group from the viewpoint of compatibility with the epoxy resin, and more preferably a triarylsulfonium salt having good heat stability. If the hydroxyalkyl group is not present in the molecule, phase separation may occur when mixed with the epoxy resin. Further, when the substituent of the sulfur atom of the sulfonium salt is an aryl group other than an aryl group, for example, an alkyl group such as a methylene group, the photocurable epoxy resin may be decomposed without irradiation with ultraviolet rays to generate an acid. Therefore, the pot life of the photocurable epoxy resin may be reduced.

In the present invention, an elastomer for obtaining flexibility, an antifoaming agent, a thixotropic agent, a diluent, and a filler such as silica for the purpose of lowering the coefficient of linear expansion and the water absorption may be added as required. It can be added at all.

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a main part of an organic electroluminescence device showing one embodiment of the present invention.

In FIG. 1, a hole injection electrode 2 is provided on a substrate 1.
Is formed on the hole injecting electrode 2, a two-layered organic thin film layer 3 of a hole transporting layer 4 and a light emitting layer 5, and an electron injecting electrode 6 is further laminated thereon. A shield member 7 is arranged around these laminates, and the lower end thereof is connected to the hole injection electrode 2 by an adhesive layer 8.

As the substrate 1, transparent or translucent glass, PET (polyethylene terephthalate), polycarbonate, amorphous polyolefin or the like is used. Further, the substrate 1 may be a flexible substrate made of any of these materials as a thin film or a flexible substrate.

As the hole injection electrode 2, ITO, ATO
(Sb-doped SnO ₂ ), AZO (Al-doped ZnO) and the like are used.

The organic thin film layer 3 has a single-layer structure of only the light-emitting layer 5, a two-layer structure of the hole-transport layer 4 and the light-emitting layer 5, or a two-layer structure of the light-emitting layer 5 and the electron-transport layer (not shown), Any of a three-layer structure of the hole transport layer 4, the light emitting layer 5, and the electron transport layer may be used.
However, in the case of such a two-layer structure or a three-layer structure,
The hole transport layer 4 and the hole injection electrode 2 or the electron transport layer and the electron injection electrode 6 are stacked so as to be in contact with each other.

The light emitting layer 5 is preferably made of a phosphor having a fluorescent property in the visible region and having good film-forming properties, such as Alq ₃ or Be-benzoquinolinol (BeBq ₂ ).
And 2,5-bis (5,7-di-t-pentyl-2
-Benzoxazolyl) -1,3,4-thiadiazole, 4,4'-bis (5,7-bentyl-2-benzoxazolyl) stilbene, 4,4'-bis [5,7-di- (2-methyl-2-butyl) -2-benzoxazolyl] stilbene, 2,5-bis (5,7-di-tert-bentyl-2-benzoxazolyl) thiofin, 2,5-
Bis ([5-α, α-dimethylbenzyl] -2-benzoxazolyl) thiophene, 2,5-bis [5,7-di- (2-methyl-2-butyl) -2-benzoxazolyl -3,4-diphenylthiophene, 2,5-bis (5-methyl-2-benzoxazolyl) thiophene,
4,4'-bis (2-benzoxazolyl) biphenyl, 5-methyl-2- [2- [4- (5-methyl-2-
Benzoxazoles such as benzoxazolyl) phenyl] vinyl] benzoxazolyl and 2- [2- (4-chlorophenyl) vinyl] naphtho [1,2-d] oxazole; 2,2 ′-(p-phenyl Range vinylene)
Benzothiazoles such as bisbenzothiazole, 2-
Fluorescent whitening agents such as [2- [4- (2-benzimidazolyl) phenyl] vinyl] benzimidazole and 2- [2- (4-carboxyphenyl) vinyl] benzimidazole, etc .; (Quinolinol) aluminum, bis (8-quinolinol) magnesium, bis (benzo [f] -8-quinolinol) zinc, bis (2-methyl-8-quinolinolate) aluminum oxide, tris (8-quinolinol) indium, tris (5- Methyl-8-quinolinol) aluminum, lithium 8-quinolinol, tris (5-chloro-8-quinolinol) gallium, bis (5-chloro-8)
-Quinolinol) calcium, poly [zinc, bis (8-
8-hydroxyquinoline-based metal complexes such as hydroxy-5-quinolinonyl) methane and metal-chelated oxinoid compounds such as dilithium epindridione;
Bis (2-methylstyryl) benzene, 1,4- (3-
Methylstyryl) benzene, 1,4-bis (4-methylstyryl) benzene, distyrylbenzene, 1,4-bis (2-ethylstyryl) benzene, 1,4-bis (3
-Ethylstyryl) benzene, styrylbenzene compounds such as 1,4-bis (2-methylstyryl) 2-methylbenzene, 2,5-bis (4-methylstyryl) pyrazine, 2,5-bis (4- Ethylstyryl) pyrazine,
2,5-bis [2- (1-naphthyl) vinyl] pyrazine, 2,5-bis (4-methoxystyryl) pyrazine,
Distilpyrazine derivatives such as 2,5-bis [2- (4-biphenyl) vinyl] pyrazine, 2,5-bis [2- (1-pyrenyl) vinyl] pyrazine, naphthalimide derivatives, perylene derivatives, oxadiazole Derivatives, aldazine derivatives, cyclopentadiene derivatives, styrylamine derivatives, coumarin derivatives, aromatic dimethylidin derivatives and the like are used. Further, anthracene, salicylate, pyrene, coronene and the like are also used.

The hole transport layer 4 is preferably a layer having a high hole mobility, being transparent and having good film-forming properties. In addition to triphenylamine derivatives such as TPD, porphine, tetraphenylporphine copper, phthalocyanine, copper phthalocyanine , Porphyrin compounds such as titanium phthalocyanine oxide, 1,1-bis {4- (di-P-tolylamino) phenyl} cyclohexane, 4,4 ′, 4 ″-
Trimethyltriphenylamine, N, N, N ', N'-
Tetrakis (P-tolyl) -P-phenylenediamine,
1- (N, N-di-P-tolylamino) naphthalene,
4,4'-bis (dimethylamino) -2-2-2'-dimethyltriphenylmethane, N, N, N ', N'-tetraphenyl-4,4'-diaminobiphenyl, N, N'-diphenyl-N , N'-Di-m-tolyl-4, N, N-diphenyl-N, N'-bis (3-methylphenyl)-
Aromatic tertiary amines such as 1,1'-4,4'-diamine, 4'-diaminobiphenyl, N-phenylcarbazole, 4-di-P-tolylaminostilbene, 4- (di-
Stilbene compounds such as P-tolylamino) -4 ′-[4- (di-P-tolylamino) styryl] stilbene, triazole derivatives, oxazizazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, Annealed amine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, silazane derivatives, polysilane-based aniline-based copolymers, polymer oligomers, styrylamine compounds, and aromatic dimethylidin-based compounds, An organic material such as poly-3-methylthiophene is used. Further, a polymer-dispersed hole transport layer 4 in which a low molecular weight organic material for the hole transport layer 4 is dispersed in a polymer such as polycarbonate is also used.

The electron transport layer may be made of a joxadiazole derivative such as 1,3-bis (4-tert-butylphenyl-1,3,4-oxadiazolyl) phenylene (OXD-7) or an anthraquinodimethane derivative. And diphenylquinone derivatives.

As the electron injection electrode 6, Al, In, M
g, metal such as Ti, Mg alloy such as Mg-Ag alloy, Mg-In alloy, Al-Li alloy, Al-Sr alloy, Al-
An Al alloy such as a Ba alloy is used. In particular, in the present invention, Al-Mg alloy or Al-Li-Mg alloy is a metal having a low work function and excellent corrosion resistance,
Especially effective.

One of the features of the present invention is that a shielding material 7 such as stainless steel or glass is used, which is adhered to the substrate 1 with an adhesive layer 8 made of a photo-curable epoxy resin to seal an organic thin film EL element. It is that you are. As for the photo-curable resin, diligent studies were made from both aspects of the waterproofness of the resin and the adhesiveness between the substrate 1 and the shield material 7. (A) an alicyclic epoxy resin having two or more epoxy groups in one molecule as a photocurable resin,
(B) an epoxy resin having one or more aromatic rings in one molecule, (C) a compound having two or more hydroxyl groups in one molecule, and (D) a functional group capable of reacting with the epoxy resin in one molecule. It has been found that a photocurable resin containing an alkoxysilyl compound and (E) a photocationic curing initiator as essential components is particularly effective.

The structure of the organic EL device manufactured according to the present invention is not particularly limited. For example, the above-described hole injection electrode (anode) 2 / hole transport layer 4 / light emitting layer 5 /
Structure other than electron injection electrode (cathode) 6, hole injection electrode 2 /
Single layer element of light emitting layer 5 / electron injection electrode 6 or double layer structure of hole injection electrode 2 / light emitting layer 5 / electron transport layer / electron injection electrode 6 and hole injection electrode 2 / hole transport layer 4 / light emission It may have a three-layer structure of layer 5 / electron transport layer / electron injection electrode 6.

The organic electroluminescent device of the present invention is different from that shown in FIG. 1 in that a hole injection electrode 2, a hole transport layer 4, a light emitting layer 5, etc. are formed on a substrate 1 as shown in FIG. After forming the organic thin film layer 3 and the electron injecting electrode 6, the coating layer 9 is coated with the photocurable epoxy resin of the present invention.
After that, the shield material 7 and the substrate 1 may be adhered with an adhesive layer 8 of a photo-curable epoxy resin.

Next, a method for manufacturing the organic electroluminescence device of the present invention will be described below.

First, a substrate 1 made of glass or the like is formed by a known method.
A hole injection electrode 2 made of ITO or the like, a hole transport layer 4 made of TPD or the like, a light emitting layer 5 made of Alq ₃ or the like,
An electron injection electrode 6 made of a Li alloy or the like is sequentially formed into a film by a resistance heating evaporation method, an ion beam sputtering method, or the like, and is laminated.

Further, as a bonding step, a shield member 7 is bonded to the substrate 1 by a bonding layer 8 of a photo-curable epoxy resin.

[0043]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The procedure for producing an organic electroluminescent device is as follows.

First, an IT is formed so as to form a predetermined pattern shape on a glass substrate 1 having an ITO film formed on the entire surface.
The hole injection electrode 2 (film thickness: 160 nm) using O was etched using hydrochloric acid. The substrate 1 was subjected to ultrasonic cleaning with a detergent (trade name “Semico Clean”, manufactured by Furuuchi Chemical Co., Ltd.) for 5 minutes, followed by ultrasonic cleaning with pure water for 10 minutes, and further with an ammonia hydrogen peroxide solution (1: 1: 5). After ultrasonic cleaning for 5 minutes with, pure water at 70 ° C. for 5 minutes,
Moisture is blown off with a nitrogen blower, and finally, it is heated and dried at a temperature of 250 ° C. The substrate 1 thus washed is set in a resistance heating evaporation apparatus, and the inside of the chamber is set to 2 × 10 ⁻⁶ T.
After the pressure was reduced to a degree of vacuum of orr or less, a hole transport layer 4 of about 500 ° was formed using TPD as an evaporation source. Then, Al
A light emitting layer 5 of about 750 ° was formed using q ₃ as a vapor deposition source.
The deposition rate is not particularly limited.
Å / s. Next, in the same vacuum layer, an electron injection electrode 6 having a thickness of 2000 ° was formed using an AlLi alloy containing 15 at% of Li as an evaporation source. Next, the substrate 1 on which the element was formed was taken out of the vacuum chamber, and a shield member 7 was formed outside the element in the following manner. SUS303 (Fe—Cr—Ni alloy) is used for the shield material 7, and a photocurable epoxy resin is applied to a portion in contact with the substrate 1 by using a dispenser, and is superimposed on the glass substrate 1 on which the element is formed. UV rays are applied from above the shielding material 7 with a high-pressure mercury lamp to 7 J to prevent damage to the layer.
/ Cm ² . In this way, an organic electroluminescence device in which the shield member 7 was bonded with the photocurable epoxy resin was manufactured.

For evaluation of the produced organic EL device, a moisture resistance test was carried out, and the results shown in (Table 1) and (Table 2) were obtained.
In this test, the defect was determined when the largest dark spot on the element surface became 50 μm or more, and the average time during which the same experiment was repeated three times was recorded.

Since Comparative Examples 3 and 4 are thermosetting resins, they were cured under the thermosetting conditions of 50 ° C. for 3 hours.
After bonding the glass substrate 1 and the shielding material 7, the same moisture resistance test as described above was performed.

All the photocurable resins used for bonding the substrate 1 and the shielding material 7 were mixed according to (Table 1) and (Table 2). The mixture was kneaded using three rolls to obtain a viscous liquid photocurable resin. The results of the moisture resistance test are summarized in (Table 1) and (Table 2).

[0048]

[Table 1]

[0049]

[Table 2]

From Tables 1 and 2, it can be seen from Examples 1 to 5
It can be seen that all have excellent moisture resistance. Comparative Examples 1 and 2 are poor in moisture resistance because they are photocurable acrylate resins of radical curing type. Comparative Examples 3 and 4
The thermosetting resin has insufficient curing due to insufficient curing.

[0051]

According to the present invention, an organic EL element is attacked by oxygen and moisture from the outside by using a photo-curing epoxy resin having a low moisture permeability and a strong adhesive force for bonding a substrate and a shielding material. Can be prevented. Further, it is possible to provide a display element which can be used in an operating environment where high reliability can be obtained and has high practicability, with little change over time due to dark spot growth and reduction in luminance.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of an organic electroluminescence element showing one embodiment of the present invention.

FIG. 2 is another configuration diagram of the organic electroluminescence element of the present invention.

FIG. 3 is a configuration diagram of a conventional organic electroluminescence element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Hole injection electrode 3 Organic thin film layer 4 Hole transport layer 5 Light emitting layer 6 Electron injection electrode 7 Shielding material 8 Adhesive layer 9 Coating layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shintaro Hara 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Sumiya Miyake 2-5-8 Higashishinagawa, Shinagawa-ku, Tokyo Sumitomo Bakelite Co., Ltd. (72) Inventor Shinji Shingo 2-5-2-8 Higashishinagawa, Shinagawa-ku, Tokyo Sumitomo Bakelite Co., Ltd.

Claims (10)

[Claims] An organic electroluminescent device comprising a laminated structure comprising an electron injection electrode, an organic thin film and a hole injection electrode on a transparent or translucent substrate, wherein the outer surface of the laminated structure is protected by a shield material. An organic electroluminescent device, wherein the transparent or translucent substrate and at least a part of the shielding material are adhered with a photocurable epoxy resin. 2. The photocurable epoxy resin comprises: (A) an alicyclic epoxy resin having two or more epoxy groups in one molecule; and (B) an epoxy resin having one or more aromatic rings in one molecule. A resin, (C) a compound having two or more hydroxyl groups in one molecule, (D) an alkoxysilyl compound having a functional group capable of reacting with an epoxy resin in one molecule, and (E) a photocationic curing initiator. The organic electroluminescent device according to claim 1, comprising a resin composition as a component. 3. An alicyclic epoxy resin having two or more epoxy groups in one molecule of (A), which is an essential component of the photocurable epoxy resin, has an epoxy equivalent of 100 or more and 200 or more.
The organic electroluminescence device according to claim 2, wherein the value is 0 or less. 4. The epoxy resin having at least one aromatic ring in one molecule of (B), which is an essential component of the photocurable epoxy resin, is a bisphenol epoxy resin, a biphenyl epoxy resin, or a novolak epoxy resin. The organic electroluminescence device according to claim 2, wherein the epoxy resin is at least one selected from the group consisting of a substituted phenol type epoxy resin. 5. The compound according to claim 2, wherein the compound having two or more hydroxyl groups in one molecule of (C), which is an essential component of the photocurable epoxy resin, is a polyhydric alcohol. Organic electroluminescent element. 6. A compound having two or more hydroxyl groups in one molecule of (C), which is an essential component of the photocurable epoxy resin, has a hydroxyl equivalent of 15,000 or less. 3. The organic electroluminescent device according to 1.). 7. An alkoxysilyl compound having a functional group capable of reacting with an epoxy resin in one molecule of (D), which is an essential component of the photocurable epoxy resin, is an alkoxysilyl compound having an alicyclic epoxy group. 3. The organic electroluminescence device according to claim 2, wherein: 8. The organic electroluminescent device according to claim 2, wherein the photocationic curing initiator (E), which is an essential component of the photocurable epoxy resin, is a sulfonium salt. 9. The organic electroluminescent device according to claim 2, wherein the photocationic curing initiator (E), which is an essential component of the photocurable epoxy resin, is a triarylsulfonium salt. 10. The photo-cationic curing initiator (E), which is an essential component of the photo-curable epoxy resin, is a triarylsulfonium salt having a hydroxyalkyl group in the molecule. The organic electroluminescent device according to the above.