JPH11144864A - Organic electroluminescent element and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent element capable of retaining stable electroluminescent property for a long duration and of preventing dark spot formation. SOLUTION: This organic electroluminescent element comprises an insulating substrate 1, an electroluminescent part constituted of a positive electrode 2, an organic electroluminescent layer 3, and a negative electrode 4 formed on the substrate, and an outer air shielding plate 6 for covering the electroluminescent part. A resin layer 7 is so formed in a gap between the substrate 1 and the outer air shielding plate 6 as to surround the electroluminescent part and seal the electroluminescent part and at the same time a gas barrier membrane 8 mainly containing silicon oxide, nitride and/or oxynitride is formed on the outside face of the resin layer 7.

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 and a method of manufacturing the same, and more particularly, to a method of sealing a thin film device which emits light by applying an electric field to a light emitting layer made of an organic compound. It is.

[0002]

2. Description of the Related Art Conventionally, as a thin film type electroluminescent (EL) element, Zn, which is a group II-VI compound semiconductor of an inorganic material, is used.
In general, S, CaS, SrS, and the like are doped with Mn or a rare earth element (Eu, Ce, Tb, Sm, or the like) which is a luminescence center. However, EL devices manufactured from the above inorganic materials include: 1) AC power supply is required (50 to 1000 Hz), 2) High drive voltage (up to 200 V), 3) It is difficult to make full color (especially blue), 4) Cost of peripheral drive circuit is high. I have.

[0003] In recent years, in order to improve the above problems, EL devices using organic thin films have been developed. In particular, in order to enhance the luminous efficiency, the type of the electrode was optimized for the purpose of improving the efficiency of carrier injection from the electrode, and a hole transport layer composed of an aromatic diamine and a luminescent layer composed of an aluminum complex of 8-hydroxyquinoline were used. Of an organic electroluminescent device provided with a device (Appl. Phys. Let
t. , Vol. 51, p. 913, 1987), the luminous efficiency is greatly improved as compared with a conventional EL device using a single crystal such as anthracene, and the practical characteristics are approached.

In addition to the electroluminescent device using a low molecular material as described above, poly (p-phenylenevinylene) (Nature, 347, 539, 1) may be used as a material for the light emitting layer.
990 et al.), Poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylenevinylene] (A
ppl. Phys. Lett. 58, 1982,
1991 et al.), Poly (3-alkylthiophene) (J
pn. J. Appl. Phys. , 30 volumes, L1938
1991, et al.) And the development of an electroluminescent device using a polymer material, and a device in which a low molecular light emitting material and an electron transfer material are mixed with a polymer such as polyvinyl carbazole (Applied Physics, vol. 61, p. 1044) , 1992).

In such an organic electroluminescent device,
Usually, a transparent electrode such as indium tin oxide (ITO) is used as an anode, and a low work function of magnesium, silver alloy, aluminum, lithium alloy, calcium, etc. is used as a cathode in order to efficiently inject electrons. Metal electrodes are used. However, these cathode materials are easily oxidized by moisture and oxygen in the atmosphere, and as a result, the cathode is separated from the organic layer, and a defect generally called a dark spot (refers to a portion that does not emit light on the light emitting surface of the device) occurs. . The number and size of dark spots in the organic electroluminescent device increase when the device is stored or driven for a long period of time, thereby causing instability of the device and shortening its life. Therefore, in order to improve the stability and reliability of the organic electroluminescent device, it is essential to seal the device to protect the device from moisture and oxygen in the atmosphere.

As a method of sealing an organic electroluminescent element, a method of molding with an acrylic resin (Japanese Patent Application Laid-Open No. 3-37991), a method of putting it together with P ₂ O ₅ in an airtight case and shielding it from the outside air (Japanese Patent Application Laid-Open No. 3-37991). No. 261091), a method of providing a protective film of a metal oxide or the like and then making it airtight using a glass plate or the like (Japanese Patent Application Laid-Open No. 4-212284), and disposing a plasma polymerized film and a photocurable resin layer on the element. (Japanese Patent Application Laid-Open No. 4-267097), and a method of holding in an inert liquid composed of fluorinated carbon (Japanese Patent Application Laid-Open No. 4-3638).
No. 90, etc.), a method in which a polymer protective film is provided and then held in silicone oil (Japanese Patent Application Laid-Open No. 5-36475). A method of bonding with a resin (JP-A-5-89959), a method of sealing in liquid paraffin or silicone oil (JP-A-5-129)
080), using a moisture-resistant photocurable resin layer to form SiO2
A method of bonding a substrate having low water permeability to an element via _two layers (JP-A-5-182759) and the like are disclosed.

[0007] However, none of the conventional methods for sealing an organic electroluminescent element has been satisfactory. For example, a method in which an element is simply sealed in an airtight structure together with a moisture absorbent does not sufficiently suppress dark spots. In addition, the method of holding in fluorinated carbon or silicone oil not only complicates the sealing step by including the step of injecting the liquid, but also does not completely prevent the increase of dark spots. In addition, there is a problem that the cathode penetrates into the interface between the cathode and the organic layer to promote the separation of the cathode. The method of directly bonding and sealing the element with an ultraviolet curable resin involves damage to the element due to a solvent contained in the adhesive and damage due to ultraviolet rays, and the stress is distorted during curing, such that the cathode is peeled off from the organic layer and the like. Absent. In a sealing method in which a photocurable or thermosetting epoxy resin is applied to the outer peripheral portion of the element and a rear glass substrate or the like is used, the moisture permeability of the cured resin itself (JIS Z020) is used.
8) is about 10 [g / m ^2/24 hr], the insufficient as a sealing adhesive for highly sensitive organic electroluminescent element to atmospheric moisture at present. The fact that the deterioration due to dark spots of the organic electroluminescent device is not improved and the light emission characteristics are unstable is a major problem as a light source for facsimile machines, copiers, backlights of liquid crystal displays, and display devices such as flat panel displays. This is an undesirable characteristic.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an organic electroluminescent device capable of preventing dark spots from occurring and maintaining excellent light emitting characteristics for a long period of time. is there.

[0009]

According to the present invention, as a result of intensive studies for achieving the above object, a resin layer is provided on the outer periphery of the element, and an outside air shielding material is adhered to the insulating substrate which supports the element. After that, it has been found that the above problem can be solved by coating the air-side surface of the resin layer with a gas barrier film made of a silicon oxide film, a nitride film or an oxynitride film, and completed the present invention. Was.

That is, the present invention provides an insulating substrate, a light emitting portion having an anode, an organic light emitting layer, and a cathode formed on the substrate, and an outside air shielding plate covering the light emitting portion. A resin layer is formed so as to surround the light emitting portion in a gap between the light emitting portion and the outside air shielding plate, and the light emitting portion is sealed, and silicon oxide, nitride and / or oxynitride is mainly formed on the outer surface of the resin layer. An object of the present invention is to provide an organic electroluminescent device formed by forming a gas barrier film as a component.

[0011]

FIG. 4 is a cross-sectional view schematically showing an example of the structure of a light-emitting portion of a general organic electroluminescent device used in the present invention. In FIG. An organic light emitting layer 3 and a cathode 4 are laminated thereon to form a light emitting portion 5. The substrate 1 serves as a support for the organic electroluminescent device, and is made of a quartz or glass plate,
Metal plates, metal foils, plastic films and sheets are used. Particularly, a glass plate or a plate of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, and polysulfone is preferable. When using a synthetic resin substrate, it is necessary to pay attention to the gas barrier property. If the gas barrier property of the substrate is too small, the organic air-emitting device may be deteriorated by outside air passing through the substrate, which is not preferable. For this reason, a method of providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate to secure gas barrier properties is also a preferable method.

An anode 2 is provided on a substrate 1. The anode 2 plays a role of injecting holes into the organic light emitting layer 3. The anode 2 is usually made of a metal such as aluminum, gold, silver, nickel, palladium, and platinum, a metal oxide such as an oxide of indium and / or tin, a metal halide such as copper iodide, carbon black, or Poly (3-
(Methylthiophene), conductive polymers such as polypyrrole and polyaniline. The formation of the anode 2 is usually performed by a sputtering method, a vacuum evaporation method, or the like. In the case of fine metal particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, or conductive polymer fine powder, they are dispersed in a suitable binder resin solution and Anode 2 by applying to
Can also be formed.

Further, in the case of a conductive polymer, a thin film can be formed directly on the substrate 1 by electrolytic polymerization, or the conductive polymer can be applied on the substrate 1 to form the anode 2. The anode 2 can be formed by laminating different materials. The thickness of the anode 2 depends on the required transparency.
When transparency is required, it is desirable that the transmittance of visible light is usually 60% or more, preferably 80% or more. In this case, the thickness is usually 5 to 1000 nm,
Preferably it is about 10 to 500 nm. If opaque, the anode 2 may have the same thickness as the substrate 1.

The organic light emitting layer 3 formed on the anode 2
It is made of a material that efficiently transports and recombines holes injected from the anode 2 and electrons injected from the cathode 4 between the electrodes to which the electric field is applied, and emits light efficiently by the recombination. Further, as shown in FIG. 4B, the organic light emitting layer 3 has a hole transporting layer 3b for improving luminous efficiency.
And the electron transport layer 3c to be of a function-separated type.

In the above-mentioned function-separated element, the material of the hole transport layer 3b is a material having a high hole injection efficiency from the anode 2 and capable of transporting the injected holes efficiently. It is desirable. For that purpose, the ionization potential is small, and the hole mobility is large.
Further, it is preferable that the material has excellent stability and hardly generates impurities serving as traps at the time of production or use.

As such a hole transport material, for example, an aromatic diamine compound in which tertiary aromatic amine units such as 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane are linked (Japanese Patent Laid-Open Publication No. 1959-19439
No. 3), 4,4'-bis [N- (1-naphthyl)-
Aromatic amines containing two or more tertiary amines represented by [N-phenylamino] biphenyl and having two or more condensed aromatic rings substituted with nitrogen atoms (JP-A-5-234681); Aromatic triamines having a starburst structure in derivatives (US Pat. No. 4,92
No. 3,774), aromatic diamines such as N, N′-diphenyl-N, N′-bis (3-methylphenyl) biphenyl-4-4′-diamine (US Pat. No. 4,764,62)
No. 5), a triphenylamine derivative which is sterically asymmetric as a whole molecule (JP-A-4-129271), a compound in which a pyrenyl group is substituted with a plurality of aromatic diamino groups (JP-A-4-175395), ethylene Diamine in which a tertiary aromatic amine unit is linked by a group
-264189), an aromatic diamine having a styryl structure (Japanese Patent Application Laid-Open No. 4-290851), a compound in which an aromatic tertiary amine unit is linked by a thiophene group (Japanese Patent Application Laid-Open No. 4-304466), a starburst type aromatic compound Aliphatic triamines (JP-A-4-308688), benzylphenyl compounds (JP-A-4-364153),
A tertiary amine linked by a fluorene group (Japanese Unexamined Patent Publication No.
No. 25473), triamine compounds (JP-A-5-252)
39455), bisdipyridylaminobiphenyl (JP-A-5-320634), N, N, N-triphenylamine derivative (JP-A-6-1972), and an aromatic diamine having a phenoxazine structure (Japanese Patent Laid-open No. −
138562), diaminophenylphenanthridine derivatives (JP-A-7-252474), silazane compounds (US Pat. No. 4,950,950), silanamin derivatives (JP-A-6-49079), phosphamine derivatives (JP-A-6-25659). These compounds may be used alone,
If necessary, they may be mixed and used.

In addition to the above compounds, polyvinyl carbazole and polysilane (Ap
pl. Phys. Lett. 59, 2760, 1
991), polyphosphazene (JP-A-5-3109)
No. 49), polyamide (JP-A-5-310949), polyvinyl triphenylamine (JP-A-7-5).
3953), a polymer having a triphenylamine skeleton (Japanese Patent Application Laid-Open No. 4-1330065), and a polymer in which triphenylamine units are linked by a methylene group or the like (Synt.
hetic Metals, 55-57, 4163
P. 1993), polymethacrylates containing aromatic amines (J. Polym. Sci., Polym. C).
hem. Ed. , 21, 969, 1983).

The hole transport layer 3b is formed by laminating the above hole transport material on the anode 2 by a coating method or a vacuum evaporation method. In the case of the coating method, one or more hole transport materials and, if necessary, an additive such as a binder resin or a coating improver which does not trap holes are added and dissolved to prepare a coating solution. Then, it is coated on the anode 2 by a method such as spin coating, and dried to form the hole transport layer 3b. Examples of the binder resin include polycarbonate, polyarylate, and polyester. If the amount of the binder resin is large, the hole mobility is reduced, so that a small amount is desirable, and usually 50% by weight or less is preferable.

In the case of the vacuum deposition method, the hole transporting material is put into a crucible placed in a vacuum vessel, and the inside of the vacuum vessel is evacuated to about 10 ^-4 Pa by a suitable pump, and then the crucible is heated. Then, the hole transport material is evaporated to form a hole transport layer 3b on the anode 2 on the substrate 1 placed facing the crucible. The film thickness of the hole transport layer 3b is usually from 10 to 300.
nm, preferably 30-100 nm. In order to uniformly form such a thin film, a vacuum deposition method is generally desirable.

Further, the efficiency of hole injection is further improved,
Further, in order to improve the adhesion of the whole organic layer to the anode, as shown in FIG.
The anode buffer layer 3a can also be inserted between the above.
The insertion of the anode buffer layer 3a has the effect of reducing the initial drive voltage of the device and suppressing the voltage rise when the device is continuously driven with a constant current. As a material used for the anode buffer layer, a uniform thin film can be formed with good contact with the anode, and is thermally stable, that is, has a high melting point and a high glass transition temperature, and a melting point of 300 ° C. or higher.
A glass transition temperature of 100 ° C. or higher is desirable. In addition, the ionization potential is low, holes can be easily injected from the anode, and the hole mobility is high.

For this purpose, porphyrin derivatives and phthalocyanine compounds (JP-A-63-29569) and star-bust-type aromatic triamines (JP-A-Hei.
No. 08688), hydrazone compounds (Japanese Unexamined Patent Publication No. 4-3)
20483), an alkoxy-substituted aromatic diamine derivative (JP-A-4-220995), p- (9-
(Anthryl) -N, N-di-p-tolylaniline (JP-A-3-111485), polythienylenevinylene and poly-p-phenylenevinylene (JP-A-4-1451)
No. 92), polyanine (Appl. Phys. Le).
tt. 64, p. 1245, 1994) and sputtered carbon films (JP-A-8-315).
No. 73) and metal oxides such as vanadium oxide, ruthenium oxide and molybdenum oxide (The 43rd Joint Lecture on Applied Physics, 27a-SY-9, 1996)
Can be used.

Examples of the compound often used as the material of the anode buffer layer include a porphyrin compound and a phthalocyanine compound. These compounds may have a central metal or may be non-metallic. Specific examples of preferred such compounds include the following compounds: porphine 5,10,15,20-tetraphenyl-21H, 23
H-porphine 5,10,15,20-tetraphenyl-21H, 23
H-porphine cobalt (II) 5,10,15,20-tetraphenyl-21H, 23
H-porphine copper (II) 5,10,15,20-tetraphenyl-21H, 23
H-porphine zinc (II) 5,10,15,20-tetraphenyl-21H, 23
H-porphine vanadium (IV) oxide 5,10,15,20-tetra (4-pyridyl) -21
H, 23H-porphine 29H, 31H-phthalocyanine copper (II) phthalocyanine zinc (II) phthalocyanine titanium phthalocyanine oxide magnesium phthalocyanine lead phthalocyanine copper (II) 4,4 ′, 4 ″, 4 ″ ′-tetraaza-29
In the case of the H, 31H-phthalocyanine anode buffer layer 3a, a thin film can be formed in the same manner as the hole transporting layer 3b. However, in the case of an inorganic substance, a sputtering method, an electron beam evaporation method, or a plasma CVD method is used. Can be

The thickness of the anode buffer layer 3a formed as described above is usually 3 to 100 nm, preferably 10 to 100 nm.
５０50 nm. An electron transport layer 3c is provided on the hole transport layer 3b. The electron transport layer 3c is formed of a compound capable of efficiently transporting electrons from the cathode in the direction of the hole transport layer 3b between electrodes to which an electric field is applied.

The electron transporting compound used for the electron transporting layer 3c is preferably a compound having a high electron injection efficiency from the cathode 4 and capable of efficiently transporting the injected electrons. For this purpose, it is preferable that the compound be a compound having a high electron affinity, a high electron mobility, and further having excellent stability and being less likely to generate trapping impurities during production or use.

Materials satisfying such conditions include 8
Metal complexes such as aluminum complexes of 10-hydroxyquinoline (JP-A-59-194393) and metal complexes of 10-hydroxybenzo [h] quinoline (JP-A-6-32)
No. 2362), bisstyrylbenzene derivatives (JP-A-1-245087 and JP-A-2-222484), rare-earth complexes (JP-A-1-256584),
Distyrylpyrazine derivatives (JP-A-2-252793) and p-phenylene compounds (JP-A-3-33183)
Japanese Patent Application Laid-Open No. 3-3), thiadiazolopyridine derivatives (Japanese Unexamined Patent Application Publication No. 3-3)
7292), pyrrolopyridine derivatives (Japanese Unexamined Patent Publication No.
37293), naphthyridine derivatives (Japanese Unexamined Patent Publication No.
No. 203982), silole derivatives (Chemical Society of Japan 70th Annual Meeting, 2D102 and 2D103, 199).
6 years).

Electron transport layer 3c using these compounds
Can generally play a role of transporting electrons and a role of providing light emission upon recombination of holes and electrons. When the hole transport layer 3b has a light emitting function, the electron transport layer 3c may only play the role of transporting electrons. For the purpose of improving the luminous efficiency of the device and changing the luminescent color, for example, a fluorescent dye for laser such as coumarin can be doped using an aluminum complex of 8-hydroxyquinoline as a host material. The advantages of this method are: 1) improved luminous efficiency by high-efficiency fluorescent dye, 2) variable emission wavelength by selection of fluorescent dye, 3) fluorescent dye which causes concentration quenching can be used, 4) fluorescent light with poor thin film property Dyes can also be used.

For the purpose of improving the driving life of the device, it is effective to dope a fluorescent dye with the electron transport layer material as a host material. For example, using a metal complex such as an aluminum complex of 8-hydroxyquinoline as a host material, naphthacene derivatives represented by rubrene (JP-A-4-335087), quinacridone derivatives (JP-A-5-70773), perylene, etc. By doping a condensed polycyclic aromatic ring (JP-A-5-198377) with 0.1 to 10% by weight based on the host material, it is possible to greatly improve the light-emitting characteristics of the device, especially the driving stability. .

The thickness of the electron transport layer 3c is usually 10 to 2
00 nm, preferably 30 to 100 nm. The electron transport layer 3c can be formed by the same method as the hole transport layer 3b, but usually, a vacuum evaporation method is used. FIG.
Examples of the single-layer organic light-emitting layer 3 that does not perform functional separation as in (A) include poly (p-phenylenevinylene) (Nature, 347, 539, 1990, etc.) and poly [2 -Methoxy-5- (2-ethylhexyloxy) -1,4-phenylenevinylene] (Appl.
Phys. Lett. 58, 1982, 1991.
Year, etc.), poly (3-alkylthiophene) (Jpn.
J. Appl. Phys. , Vol. 30, L1938, 1
991 et al.) And a system in which a light emitting material and an electron transfer material are mixed with a polymer such as polyvinyl carbazole (Applied Physics, Vol. 61, p. 1044, 1992).

As a method for further improving the luminous efficiency of the organic electroluminescent device, an electron injection layer (not shown) can be further laminated on the organic luminescent layer 3. The compound used for the electron injection layer is required to be capable of easily injecting electrons from the cathode and having a higher electron transport ability.
Examples of such electron transport materials include 8-hydroxyquinoline aluminum complexes and oxadiazole derivatives (Appl. Phys. Lett., 5
5, p. 1489, 1989, etc.) and a system in which they are dispersed in a resin such as polymethyl methacrylate (PMMA) (A
ppl. Phys. Lett. , 61, 2793,
1992), phenanthroline derivatives (JP-A-5-3
No. 31459), 2-t-butyl-9,10-N,
N'-dicyanoanthraquinone diimine (Phys. S
tat. Sol. (A), 142, 489, 199
4 years), n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, n-type zinc selenide, and the like. The thickness of the electron injection layer is usually 5 to 200 nm, preferably 10 to 100 nm.
nm.

The cathode 4 plays a role of injecting electrons into the organic light emitting layer 3. As the material used for the cathode 4, the material used for the anode 2 can be used. However, for efficient electron injection, a metal having a low work function is preferable, and tin, magnesium, indium, calcium,
A suitable metal such as aluminum or silver or an alloy thereof is used.

Specific examples include a magnesium-silver alloy,
Low work function alloy electrodes such as a magnesium-indium alloy and an aluminum-lithium alloy are exemplified. further,
L is applied to the interface between the cathode 4 and the organic light emitting layer 3 or the electron transport layer 3c.
Inserting an ultra-thin film (0.1 to 5 nm) such as iF or Li ₂ O is also an effective method for improving the efficiency of the device.
The thickness of the cathode 4 is usually the same as that of the anode 2. In order to protect the cathode made of low work function metal,
Stacking a metal layer having a high work function and being stable to the atmosphere increases the stability of the device. For this purpose, metals such as aluminum, silver, nickel, chromium, gold, platinum and the like are used.

The structure opposite to that shown in FIG.
It is also possible to laminate the cathode 4, the organic light emitting layer 3, and the anode 2 in this order on the substrate. As described above, at least one of the two substrates is highly transparent and the organic electroluminescent device of the present invention is disposed between the two substrates. It is also possible to provide. 4 (B) and FIG.
It is also possible to laminate in a structure opposite to the above-mentioned respective layer constitutions shown in (C). In order to improve the stability and reliability of the organic electroluminescent device, it is necessary to seal the entire device. Hereinafter, the sealing method of the present invention will be described with reference to the structural example of FIG.

Since the cathode of the organic electroluminescent device has a low work function, it is oxidized particularly by moisture, and the oxidized portion tends to have a high resistance or peel off from the organic layer, so that a dark spot is easily generated. Therefore, in order to suppress the dark spot, first, the light emitting unit 5 must be placed in an airtight structure in which moisture from outside air is blocked. As a specific method of sealing the light emitting unit 5 in an airtight structure, a plate-shaped or sheet-shaped outside air shielding plate 6 having gas barrier properties is placed opposite to the insulating substrate 1 supporting the light emitting unit 5 and a resin is formed. 7 is applied so as to surround the periphery of the light emitting unit 5, and bonded and sealed. As the outside air shielding plate 6, those already mentioned as the insulating substrate 1 can be used, and a quartz or glass plate, a metal plate or a metal foil, a plastic film or a sheet, or the like is used.

In particular, a glass plate and a plate of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferred. When using a synthetic resin substrate, it is necessary to pay attention to the gas barrier property, and it is desirable to provide a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate to secure the gas barrier property. A resin layer 7 is used to bond the insulating substrate 1 and the outside air shielding plate 6. As a material used for the resin layer 7, an epoxy resin is preferable in consideration of gas barrier properties. Examples of the epoxy-based resin include a light-curing type and a thermosetting type.
Examples of the photocurable epoxy resin include 30Y-184G manufactured by Three Bond Co., Ltd. and XNR5493T manufactured by Chise Nagase Co., Ltd.
And the like. Examples of the thermosetting epoxy resin include XNR5155 manufactured by Nagase Chiba Co., Ltd. In addition, room temperature curing type Araldite or modified epoxy elastic adhesive manufactured by Ciba Geigy Co., Ltd., for example, EP-001 manufactured by Cemedine Co., Ltd., MOS7 manufactured by Konishi Co., Ltd., and Varian Torr Seal manufactured by Varian Co., Ltd. And the like.

[0035] However, the moisture permeability of the resin layer is at most 10 [g / m ^2/24 hr] (JIS Z0208) about practically insufficient. Accordingly, the gas barrier property is insufficient with only the resin layer 7 shown in FIG. 3 that blocks moisture from the outside air. In the present invention, in view of the above points, as shown in FIG. 1, it is effective to provide a gas barrier film 8 having excellent gas barrier properties on the outside of the resin layer 7 to effectively block moisture in the outside air. I found it. Fig. 1 at the top (outside air shielding plate)
FIG. 2 shows a view from the side. Reference numeral 9 denotes the resin layer 7 and the light emitting body 5
The gas barrier film 8 is provided on the outside of the portion provided on the outer peripheral portion of FIG. 2a indicates an extraction electrode portion of the anode, and 4a indicates an extraction electrode portion of the cathode. The gas barrier film 8 is formed so as to leave a contact portion with these external circuits.

As the gas barrier film 8, a film mainly composed of a silicon oxide film, a nitride film and / or an oxynitride film is used. When the silicon oxide film is represented by SiOx, the composition ratio x is preferably in the range of 1.0 to 2.0. When the silicon nitride film is represented by SiNx, the composition ratio x is 0.5 to
It is preferably in the range of 1.3. When a silicon oxynitride film (oxynitride) is represented by SiOxNy, x
And y are x = 0.1 to 1.8, y = 0.1 to 1.0;
It is preferable that each of them is in the range of x + y <2.0. Further, in order to reduce silicon dangling bonds in the gas barrier film, 0.1 to 10 wt. It is also effective to contain% hydrogen or carbon atoms.

The gas barrier film has a thickness of 10 nm to 1
It is preferably in the range of 0 μm. If the thickness is less than 10 nm, moisture in the outside air may pass through the film due to defects. When the thickness is 10 μm or more, the stress of the film increases, and phenomena such as peeling occur, which is not preferable. The gas barrier film is formed by any one of a plasma CVD (chemical vapor deposition) method, a reactive vacuum deposition method, and a sputtering method.

The plasma CVD method is roughly classified into two types, namely, a capacitive coupling type and an inductive coupling type. Either method is adopted. In the capacitive coupling type, a plasma is generated by two opposing electrodes, and a film is formed by introducing a source gas. FIG. 5 shows the capacitive coupling method. In this method, the electrode 12 connected to the high frequency power supply 11 through the matching device 10 serves as a cathode, and the electrode 13 grounded serves as an anode. The sample 14 to which the gas barrier film is applied may be placed on any electrode. However, when a negative bias voltage is to be applied, the substrate sample is placed on the cathode side as shown in FIG. On the other hand, in the inductively coupled plasma CVD method, a sample is usually placed in a glass or quartz tube that can be evacuated, and a coil is wound around the tube for a required number of turns, and a high frequency power supply is connected to the coil through a matching device. Thereby, plasma can be generated in the tube.

As a source gas used for forming the gas barrier film by the plasma CVD method, an organic silicon compound can be used. In order to use this compound for the plasma CVD method, it is preferable that the compound has a vapor pressure of about 1 Torr in the range of room temperature to 100 ° C. Specific examples of compounds having such properties are shown below, but the present invention is not limited to these compounds in any way:
For example, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, tetramethylsilane, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, dimethyl Diethoxysilane, diethoxysilane, triethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, vinyltris (2-methoxyethoxy) silane, trimethylethoxysilane, vinyltriacetoxysilane, ethyltriethoxysilane, tetrakis (2-methoxyethoxy) silane, tetrakis (2-ethylhexoxy) silane, tris (trimethylsiloxy) silane, trimethoxyvinylsilane,
Trimethylvinylsilane, methylphenyldimethoxysilane, triethoxychlorosilane, n-propyltrimethoxysilane, tetrakis (2-ethylbutoxy) silane, n-octyltriethoxysilane, acetoxypropyltrimethoxysilane, tris (trimethylsiloxy) phenylsilane, octa Methylcyclotetrasiloxane, octamethyltrisiloxane, 1,2,3,3-
Tetrakis (trimethylsiloxy) disiloxane, 1,
2,3,3-tetramethyldisiloxane, pentamethyldisiloxane, N, O-bis (dimethylsilyl) acetamide, 1,3-divinyl-1,1,3,3-teramethyldisiloxane, 1,3- Diethoxytetramethyldisiloxane, 1,1,3,3,5,5-hexamethylcyclotrisilazane, 1,3,5,7-tetramethylcyclotetrasiloxane, bis (trimethylsiloxy) ethylsilane, 1,1, 3,3-tetramethyldisilazane, hexamethyldisilazane, 1-trimethylsilyl-1,2,2
4-triazole, piperidinotrimethylsilane, tetrakis (dimethylamino) silane, heptamethyldisilazane, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, and 1,1,3,3, 5,5-hexamethylcyclotrisilazane can be mentioned.

A siloxane-based compound is used for the silicon oxide film, a silazane-based compound is used for the silicon nitride film, and a silicon oxynitride film is a mixture of one or both compounds. Is preferred. As a gas used in the plasma film formation, in order to increase reactivity in addition to the vapor organosilicon compound, in the case of an oxide film, oxygen, carbon monoxide, carbon dioxide, or the like is used as an oxidizing gas, and a nitride film is used. In this case, nitrogen and ammonia are used, and in the case of an oxynitride film, nitrous oxide, nitrogen dioxide and the like are used. Further, a rare gas such as helium or argon is appropriately added as a diluting gas.

The gas pressure during plasma film formation is 1 mTorr to
The range is preferably 10 Torr, and the substrate temperature during processing is 0
The temperature is preferably in the range of 150 to 150 ° C. The power frequency is 1
The range of 0 kHz to 100 MHz is preferred. The range of the substrate bias voltage in the capacitive coupling type is preferably in the range of -30 to -1000V. The use of microwave plasma or plasma in ECR mode is also suitable for the purpose of the present invention.

When a silicon-containing evaporation source is evaporated in a vacuum by a reactive vacuum evaporation method to deposit the silicon on a substrate,
50 mT of reactive gas whose atmosphere is given by plasma CVD
It flows into the reaction vessel at a pressure of about orr to form a film. In the case of a silicon oxide film, it is preferable to use oxygen.
At this time, it is also a good method that plasma is generated between the evaporation source and the substrate by a coil or the like, and the plasma is deposited by an ion plating method. As a deposition source in the case of an oxide film, SiO is used in the resistance heating method, and Si, SiO,
SiO ₂ is preferably used.

In the sputtering method, SiO 2 is used as a target.
₂ , a desired gas barrier film can be obtained by forming a film in the above-mentioned reactive gas using Si ₃ N ₄ or the like. In any of the above film forming methods, it is also effective to insert an adhesive layer in order to increase the adhesion between the resin layer and the gas barrier film. When a silicon oxide film is used, the adhesive layer is preferably a film having a lower oxygen content and a higher silicon content than the gas barrier film, and it is preferable that x is less than 1 in the composition formula of SiOx. The same applies to nitride films and oxynitride films. The thickness of the adhesive layer is preferably in the range of 0.5 nm to 0.5 μm. Taking the plasma CVD method as an example, the adhesive layer can be easily formed from the source gas of the gas barrier layer without using a reactive gas (including an oxygen source and a nitrogen source). The present invention can be applied to any of a single element, an element having a structure in which the organic electroluminescent elements are arranged in an array, and a structure in which an anode and a cathode are arranged in an XY matrix.

[0044]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the description of the following examples unless it exceeds the gist. Example 1 An organic electroluminescent device having a light emitting portion structure shown in FIG. 4C was manufactured by the following method. Indium on glass substrate
A tin oxide (ITO) transparent conductive film deposited to a thickness of 120 nm (manufactured by Geomatics Co .; electron beam film-formed product; sheet resistance: 15Ω) is patterned into a 2 mm-wide stripe using ordinary photolithography technology and hydrochloric acid etching to form an anode. Was formed. The patterned ITO substrate is cleaned in the order of ultrasonic cleaning with acetone, water cleaning with pure water, and ultrasonic cleaning with isopropyl alcohol, dried with nitrogen blow, and finally cleaned with ultraviolet and ozone, and placed in a vacuum evaporation apparatus. installed. After the rough evacuation of the above apparatus was performed by an oil rotary pump, the degree of vacuum in the apparatus was 2 × 10 ⁻⁶ Torr.
R (about 2.7 × 10 ⁻⁴ Pa) or less was evacuated using an oil diffusion pump equipped with a liquid nitrogen trap. Copper phthalocyanine (crystal form is β-form) shown below, which was put in a molybdenum boat placed in the above apparatus, was heated for vapor deposition. Degree of vacuum 2 × 10 ⁻⁶ Torr (about 2.7 × 10 ⁻⁴ P
a), evaporation was performed for one minute to obtain an anode buffer layer 3a having a thickness of 20 nm.

[0045]

Embedded image

Next, the following 4,4'-bis [N- was placed in a ceramic crucible placed in the apparatus.
(1-Naphthyl) -N-phenylamino] biphenyl was deposited by heating with a tantalum wire heater around the crucible.

[0047]

Embedded image

At this time, the temperature of the crucible is from 250 to 260
The temperature was controlled in the range of ° C. Degree of vacuum at the time of vapor deposition 1.7 × 10 ^-6 T
A hole transport layer 3b having a film thickness of 60 nm was obtained at an orr (about 2.3 × 10 ⁻⁴ Pa) and a deposition time of 3 minutes and 30 seconds. Subsequently, an 8-hydroxyquinoline complex of aluminum (Al (C ₉ H ₆ NO) ₃ ) represented by the following structural formula is used as a host material of the electron transporting layer 3 c having a light emitting function, and rubrene represented by the following structural formula is used as a doped dye. Was subjected to binary deposition using separate crucibles.

[0049]

Embedded image

At this time, the crucible temperature of the aluminum 8-hydroxyquinoline complex is in the range of 270 to 300 ° C.
The temperature of the crucible of rubrene is controlled in the range of 150 to 160 ° C., and the degree of vacuum at the time of deposition is 1.3 × 10 ⁻⁶ Torr (approximately 1.
7 × 10 ⁻⁴ Pa), the deposition time was 3 minutes and 10 seconds, and the thickness of the deposited electron transport layer was 75 nm. The substrate temperature during vacuum deposition of the above-described anode buffer layer 3a, hole transport layer 3b, and electron transport layer 3c was kept at room temperature.

Here, vapor deposition up to the electron transport layer 3c is performed.
Once removed element from the vacuum evaporation system to the atmosphere
2 mm wide stripes as a mask for cathode deposition
Make the shadow mask orthogonal to the ITO stripe of anode 2.
In a vacuum deposition apparatus
And the degree of vacuum in the apparatus is 2 × 10 ^-6
Torr (about 2.7 × 10^-FourExhaust until below Pa)
did. Then, as the cathode 4, an alloy of magnesium and silver
The electrode is made to have a thickness of 44 nm by a binary simultaneous evaporation method.
Was deposited. Vapor deposition using molybdenum boat
1x10^-FiveTorr (about 1.3 × 10^-3Pa), during evaporation
For 3 minutes and 20 seconds. Also, the atoms of magnesium and silver
The ratio was 10: 1.4. Subsequently, the vacuum of the device is reduced.
Do not break the aluminum using a molybdenum boat
Laminated on a magnesium-silver alloy film with a thickness of 40 nm
Thus, the cathode 4 was completed. The degree of vacuum during aluminum deposition
1.5x10^-FiveTorr (about 2.0 × 10^-3Pa), steam
The wearing time was 1 minute and 20 seconds. More magnesium and silver
The substrate temperature during the deposition of a two-layer cathode of alloy and aluminum is
It was kept at room temperature.

As described above, an organic electroluminescent device having a size of 2 mm × 2 mm was obtained. After the device was taken out of the cathode vapor deposition device, the device was sealed according to the structure shown in FIGS. First, after replacing the evaporation mask with a shadow mask covering the entire element portion, the above-described element is installed again in the above-described cathode evaporation apparatus, and the GeO film is formed on the cathode 4 in the same manner as described above. 200n film thickness
m to form a protective layer. The degree of vacuum at this time is 1.5
x10 ^-6 Torr, deposition time was 5 minutes, and substrate temperature was room temperature. The device was taken out of the above device into the atmosphere, and a photocurable resin (30Y-184G manufactured by Three Bond Co.) was applied to a glass plate of the same material and thickness as the substrate as an outside air blocking material as shown in FIG. After that, 4
It was cured by exposure to J / cm ² radiation.

Next, the element sealed with the photocurable resin is set in a reaction chamber of a capacitively coupled plasma CVD apparatus,
The degree of vacuum in the container is 1 × 10 ^-5 Torr by the oil diffusion pump
(Approximately 1.3 × 10 ⁻³ Pa). Then, 1,1,3,3-tetramethyldisiloxane 8SCCM, oxygen 8SCCM, helium 8S
CCM is introduced into the vessel and the pressure is increased to 50-60 mTorr.
After adjusting to the range, a power source having a frequency of 110 kHz was plasma-generated at a power density of 0.5 W / cm ² on the substrate holder on which the element was installed. The substrate bias voltage at this time is -4
00V. A gas barrier film having a thickness of 0.7 μm was laminated on the resin layer by forming the film for 5 minutes. When the composition of this gas barrier film was analyzed by X-ray photoelectron spectroscopy, it was found that SiO _1.9 C
_0.4 , and a hydrogen atom is 2 by FT-IR measurement.
Atomic% was found to be contained. In addition, the moisture permeability of the gas barrier film obtained by laminating the above gas barrier film on the photocurable resin layer is 0.1 mm.
Was ² [g / m 2/24 hr] (JIS Z0208).

The organic electroluminescent device thus obtained was left in an environmental tester set at a temperature of 80 ° C. and a relative humidity of 90%, and the light emission luminance and dark spot area were measured. The brightness and the voltage are values in the case of driving at a current of 15 mA / cm ² . For the measurement of the dark spot, the light emitting surface of the element was photographed with a CCD camera, and then binarized by image analysis to quantify. Table 1 shows the measured changes over time.
Shown in The growth of dark spots could be suppressed to a level that would not be a problem in practical use.

[0055]

[Table 1]

Comparative Example 1 A sealing element was produced in the same manner as in Example 1 except that no gas barrier layer was provided. Table 2 shows the results of the environmental test at 80 ° C.-90%. After storage for 48 hours, many dark spots having a diameter of 250 μm were generated.

[0057]

[Table 2]

Example 2 After curing a photocurable resin (XNR5493T) manufactured by Nagase Chiba Co., Ltd. at an irradiation exposure dose of 12 J / cm ² , a plasma CVD film was formed without adding oxygen as a sublayer of a gas barrier film. .1 μm carbon-rich film (composition ratio: SiCxOy;
x = 0.6, y = 0.8), except that a sealing element was formed in the same manner as in Example 1. Table 3 shows the results of the environmental test measurement at 80 ° C.-90%. The voltage rise was small, and the dark spot was sufficiently suppressed.

[0059]

[Table 3]

Comparative Example 2 A sealing element was produced in the same manner as in Example 2 except that no gas barrier layer was provided. Table 4 shows the environmental test results at 80 ° C.-90%. After storage for 48 hours, a significant increase in dark spots was observed.

Example 3 A gas barrier film was formed in the same manner as in Example 1, except that 16 SCCM of N ₂ O was used instead of oxygen as a source gas at the time of forming the gas barrier film. The composition of this film was subjected to the same environmental test as in Example 1, but the area ratio of dark spots was less than 1% even after storage for 48 hours.

Example 4 An element sealed with a photocurable resin in the same manner as in Example 1 was set in a reactive vacuum evaporation apparatus, and the degree of vacuum in the container was set to 1 × 10 ^-6 Torr by an oil diffusion pump. (About 2.7x10
^-4 Pa) or less. Subsequently, oxygen is introduced as a reactive gas, the pressure is adjusted to 10 to 5 Torr, and then the evaporation source SiO in the metal boat is evaporated by resistance heating to form a 0.5 μm gas barrier film on the resin layer. did. When the composition of this gas barrier film was analyzed by X-ray photoelectron spectroscopy, it was SiO _1.6 . Moreover, the moisture permeability of the gas barrier film laminated on the photocurable resin layer is 0.3 [g].
/ M ^2/24 hr] was (JIS Z0208).
An environmental test similar to that of Example 1 was performed, but the area ratio of dark spots was less than 1% even after 48 hours.

[0063]

[Table 4]

[0064]

According to the method for sealing an organic electroluminescent device of the present invention, since a specific gas barrier layer is provided on a sealing resin layer, storage and driving can be performed without being affected by moisture in the atmosphere. In this case, a sealing element exhibiting stable light emission characteristics can be obtained. Therefore, the organic electroluminescent device according to the present invention can be used as a light source (for example, a light source of a copier, a light source of a copier,
It can be applied to liquid crystal displays and backlight sources for instruments, display panels, and sign lights, and its technical value is great.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of the organic electroluminescent device of the present invention.

FIG. 2 is a plan view of the organic electroluminescent device of FIG.

FIG. 3 is a longitudinal sectional view of a conventional organic electroluminescent device.

FIG. 4 is a longitudinal sectional view showing a structure of a light emitting unit.

FIG. 5 is an explanatory view showing a gas barrier film forming method by plasma CVD.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Organic light emitting layer 3a Hole transport layer 3b Electron transport layer 4 Cathode 5 Light emitting part 6 Outside air shielding plate 7 Resin layer 8 Gas barrier film

Claims (10)

[Claims] 1. An insulating substrate, a light emitting portion having an anode, an organic light emitting layer and a cathode formed on the substrate, and an outside air shielding plate covering the light emitting portion, and the substrate and the outside air shielding plate A resin layer is formed so as to surround the light emitting portion in a gap between the light emitting portion and the light emitting portion, and a gas barrier mainly composed of silicon oxide, nitride and / or oxynitride is formed on the outer surface of the resin layer. An organic electroluminescent device characterized by comprising a film. 2. A gas barrier film having a thickness of 10 nm to 10 nm.
2. The organic electroluminescent device according to claim 1, wherein said organic electroluminescent device is in a range of μm. 3. The organic electroluminescent device according to claim 1, wherein the resin layer contains a photo-curable epoxy resin as a main component. 4. The organic electroluminescent device according to claim 1, wherein the resin layer contains a thermosetting epoxy resin as a main component. 5. The organic electroluminescent device according to claim 1, wherein the gas barrier film is formed on an outer surface of the resin layer via an adhesive layer. 6. A light emitting portion having an anode, an organic light emitting layer and a cathode is formed on an insulating substrate, and the light emitting portion is covered with an outside air shielding plate, and the light emitting portion is surrounded by a gap between the substrate and the outside air shielding plate. A light emitting portion is sealed by forming a resin layer so that a gas barrier film containing silicon oxide, nitride and / or oxynitride as a main component is formed on the outer surface of the resin layer. A method for producing an organic electroluminescent device, which is characterized by the following. 7. The method according to claim 6, wherein the gas barrier film is formed by a reactive plasma CVD method using an organic silicon compound as a raw material. 8. The method according to claim 6, wherein the gas barrier film is formed by a reactive vacuum deposition method. 9. The method according to claim 6, wherein the gas barrier film is formed by a sputtering method. 10. The method for manufacturing an organic electroluminescent device according to claim 6, wherein an adhesive layer is provided between the resin layer and the gas barrier film.