WO2004008812A1

WO2004008812A1 - Flexible organic electroluminescence element and production method therefor and information display unit and lighting device

Info

Publication number: WO2004008812A1
Application number: PCT/JP2003/008889
Authority: WO
Inventors: Makoto Takamura
Original assignee: Rohm Co., Ltd.
Priority date: 2002-07-15
Filing date: 2003-07-14
Publication date: 2004-01-22
Also published as: JP2004047381A

Abstract

An organic electroluminescence element comprising, sequentially laminated on a flexible plastic substrate (10), a transparent electrode layer (11), a light emitting layer (13) consisting of an organic electroluminescence, and a metal electrode layer (14), the light emitting layer (13) being sealed with a plastic sealing plate (15a), characterized in that the surface, on which the light emitting layer (13) is not formed, of the substrate (10) is sealed with a plastic sealing plate (15b). As a result, a flexible organic EL element using a plastic substrate is improved in sealing structure, reduced in features to permeate water content and oxygen, and restricted in deterioration of element luminous performance.

Description

Specification

Flexible organic electorifice · Luminescent element, its manufacturing method and information

Technical field

The present invention relates to an organic light emitting element, which is an electric light emitting element used as a backlight for a liquid crystal display or a light source for display-optical communication, etc., and particularly to a sealing structure for improving reliability. The present invention relates to a flexible organic electrifying port luminescent element and a manufacturing method thereof, and an information display device and an illuminating device including an organic electroluminescent element.冃景. Technology

Electroluminescence is a light-emitting device that uses a phenomenon called electroluminescence of solid fluorescent substance or elect-port luminescence. Various types of e-light are displayed on the display unit of the display device. In addition, an organic EL device using an inorganic material as a luminous body has been put to practical use, and is being developed for application to a backlight / flat display of a liquid crystal display. However, inorganic EL devices require AC and a high voltage of about 100 V to emit light, and because it is difficult to emit blue light, full color uniformization by the three primary colors R, G, and B of light is difficult. There are drawbacks such as difficulty.

On the other hand, research on EL devices using narcotics has been carried out for a long time, but the efficiency is so low that only low brightness can be obtained and full-scale practical research has not been completed. However, the structure proposed by Kodak's CW Tang in 1987, that is, an organic EL device having a function-separated stacked structure in which an organic substance is divided into two layers, a hole transport layer and a light-emitting layer, has a low voltage of 10 V or less. High-brightness light emission of 1000 cd / m ² or more was realized despite the voltage (CW Tang and SA Vans 1 ke: App 1. Pys. Lett, 51 (1987) 913). As a result, OLEDs have suddenly attracted attention. In recent years, stacked OLEDs with the same configuration Research on children has been actively conducted.

Here, the configuration of the organic EL element of = ^ will be briefly described with reference to FIG. Conventionally, a structure in which a glass or metal sealing plate is bonded to the back side of an organic EL element formed on a glass substrate has been mainly used. In FIG. 6, a hole injection 31 made of a transparent electrode film such as IT0 formed by a sputtering method or a vacuum evaporation method on a transparent glass substrate 30 is laminated as an anode, and this hole injection 31 is formed. A hole transport layer 32 such as TPD (N, N'-diphenyl-1-N, N, 1-bis (3-methylphenyl) -11, -diphenyl-1,4'-diamine) is formed on the substrate. . Then, on the hole transport layer 32, a light emitting layer 33 using Alq3 (8-hydroxy quinoline aluminum) or the like is formed by a vacuum deposition method, and an electron injection electrode is formed on the light emitting layer 33. 34 is stacked as a cathode. This electron injection is mainly made of a metal film having a low work function, such as AlLi or MgAg. Recombination is performed by applying a positive DC voltage to the hole injection S 直流 31 and a negative DC voltage to the electron injection electrode 34 to the organic EL element of this configuration, thereby generating excitons, and finally shifting from the excited state to the ground state. The light emission occurs. In an organic EL device having such a light-emitting principle, an arbitrary emission wavelength can be easily controlled by changing the light-emitting material and layer structure, so that it can be applied to various light-emitting devices, lighting elements, and full-color displays. Be expected.

As described above, the organic EL element emits electrons directly from the electron injection m @ 34 or into the light emitting layer 33 through the electron transport layer, and emits light from the hole injection 31 directly or through the hole transport layer 32. Light is emitted by recombination with holes injected into the layer 33. In order to improve the light emission characteristics of an organic EL device based on such a light emission mechanism, mainly, 1) improvement of an organic film such as a light emitting layer 33 and a hole transport layer 32, 2) a hole injection electrode 31 and electron injection. The electrode 34 needs to be improved. Of these, the improvement of the cathode material of the electron injection electrode 34 in 2) is intended to make it easier for electrons to enter the light emitting layer, so the barrier between the electron injection electrode 34 and the light emitting layer 33 must be reduced. No. Therefore, the material of the electron injection electrode 34 needs to have a small work function and a high electric conductivity. For example, MgAg (U.S. Pat. No. 4,885,2111) and A 1 L i ( Japanese Patent Application Laid-Open No. 5-12 1172) is generally used. I have.

By the way, these alloys are very active and chemically unstable. As a result, the cathode material is corroded and oxidized by moisture and oxygen from the outside, causing significant growth of non-light-emitting portions called dark spots on the light-emitting surface and temporal deterioration such as a decrease in luminance. It will be easier. Organic solids such as the light emitting layer 33 and the hole transporting layer 32 used in the organic EL device are generally susceptible to moisture and oxygen, and similarly cause dark spot growth and reduced brightness. Therefore, for practical organic EL devices and devices using them, the devices must be sealed for the purpose of preventing moisture and oxygen from entering the organic material and the S material, thereby increasing reliability.

In the conventional organic EL display element, since a sealing plate 35 made of glass, metal, or glass is bonded to the glass substrate 30, it cannot be bent (not flexible). There were drawbacks, such as easy cracking and heavy weight when subjected to impact. As a means for solving these drawbacks, a method has been proposed in which a plastic substrate is used instead of a glass substrate and a glass or metal sealing plate. However, according to this method, the above-mentioned disadvantage is solved, but as described above, the organic EL element is liable to deteriorate in light emitting performance due to moisture or oxygen entering from the outside. In addition, a plastic substrate, which is considered to have high oxygen permeability, has a problem that a practical device life cannot be maintained. In addition, since organic EL elements use an organic material in the light-emitting layer, they generally have a drawback in that when the temperature exceeds their glass point transfer temperature, crystallization of the organic substance occurs and the light emission characteristics of the element rapidly deteriorate. there were. Therefore, in the manufacturing process after the organic light emitting layer is laminated, the temperature cannot be raised from 80 to 100 ° C. or more. Therefore, in the step of attaching and adhering the sealing plate, an ultraviolet curable resin is used for the adhesive instead of a thermosetting epoxy resin generally used for liquid crystal displays and the like. However, UV-curable resins containing acryl or epoxy resin as a main component have higher moisture and oxygen permeability than thermosetting epoxy resins and the like. This is another important issue for improving device life.

The present invention solves these problems by providing a flexible organic EL device using a plastic substrate with an improved sealing structure and reduced moisture and oxygen permeability. By doing so, the object is to suppress inferiority of the device light emitting performance. At the same time, the objective is to commercialize the organic EL device for various information display devices and lighting devices.

In order to achieve these objectives, the selection of plastic sealing plate members and structures is an important issue. As mentioned above, a sealing plate is essential for an organic EL device to protect it from moisture and oxygen. However, in order to avoid exceeding the glass transition temperature when bonding the organic EL device * | and the sealing plate, an ultraviolet curing resin is used as the adhesive. In a flexible organic EL device using a plastic substrate, it is necessary to reduce moisture and oxygen entering from the entire surface of the plastic substrate and the plastic sealing plate and from the bonding surface. Organic EL devices, on the other hand, have a transparent (anode) extraction terminal and a metal electrode (cathode) bow I extraction terminal. The frame terminal for connecting these to the drive circuit is drawn out of the sealing plate, so the frame terminal One of the important issues is how to bond the sealing plate with the sealing plate. Disclosure of the invention

In order to achieve the above-described object, the invention of the present application is to sequentially laminate a transparent electrode layer, a light-emitting layer composed of organic electodes and luminescence, and a metal electrode layer on a flexible plastic substrate. An organic electroluminescent element sealed with a plastic sealing plate, wherein a surface on which the light emitting layer is not formed is sealed with a plastic sealing plate. -It is a luminescence element.

With this configuration, even in the case of an organic electroluminescence element using a flexible plastic having a high moisture and oxygen permeability, the surface of the flexible plastic substrate on which the light emitting layer is not formed is made of plastic. Since the sealing plate is used for sealing, the use of plastic having low hygroscopicity for the sealing plate can prevent the device light emission performance from deteriorating due to moisture or oxygen entering from the outside. As a result, it is possible to provide a flexible organic EL element having a practical element life and a long display life while the display screen is bent. In addition, since the sealing plate is also made of plastic, the entire organic EL port of the luminescent element is fluorinated. Can be rexible.

At least one of a sealing plate for sealing the light emitting layer and a sealing plate for sealing the substrate can be bonded to the substrate with an ultraviolet curing resin. Since this is possible at a low temperature of 100 ° C. or less, it is particularly effective when a material such as PET (polyethylene terephthalate) having low heat resistance is used for a flexible plastic substrate. At least one of the sealing plate for sealing the light emitting layer or the sealing plate for sealing the substrate can be bonded to the substrate with a thermosetting resin. This is effective when using PES (polyethersulfone) or the like that has relatively high heat resistance for the substrate, making good use of the thermal conductivity lower than glass, heating only the adhesive part locally, Organic electrification which is weak to heat ・ The element substrate and the sealing plate can be bonded without affecting the luminescence element. Further, the resin after thermosetting is low in moisture permeability and oxygen permeability, is the most reliable bonding method, and can provide a highly reliable organic electroluminescent device.

At least one of a sealing plate that seals the light emitting layer or a sealing plate that seals the substrate and the substrate can be bonded with an epoxy resin that starts curing by mixing a main agent and a curing agent. . This is particularly effective when plastic materials with low heat resistance are used for flexible plastics because they can be bonded at room temperature.

A gas barrier layer can be formed on one or both of the inner surface of the sealing plate for sealing the light emitting layer and the inner surface of the sealing plate for sealing the substrate. By doing so, a gas barrier layer formed by stacking a silicon oxide film or a nitride film formed by a method such as a vacuum evaporation method, or a laminated film thereof and a metal film such as aluminum is used as a sealing plate. By forming it on the inner surface, the intrusion of moisture can be further prevented, and a long-life organic electroluminescence device can be obtained.

One or both of a sealing plate for sealing the light emitting layer and the substrate, or a sealing plate for sealing the substrate and a space formed by the substrate is filled with a silicone oil-based or fluorine-based inert liquid. Can be done. By filling the surface of the flexible plastic substrate where the light-emitting layer is not formed, that is, the inner surface of the sealing plate on the display surface side, with dimethyl silicone oil or a fluorine-based inert liquid, light scattering occurs. It is possible to suppress a decrease in the external extraction efficiency and promote heat radiation from the organic EL element. In addition, the surface of the flexible plastic substrate on which the light emitting layer is formed, that is, the space between the sealing plate on the non-display surface side and the surface of the organic EL element is filled with an inert liquid in the same manner as described above. The organic EL element can be protected by dissipating heat from the element and dispersing external mechanical stress in the liquid.

One or both of the inner surface of the sealing plate for sealing the light emitting layer and the inner surface of the sealing plate for sealing the substrate may contain a moisture absorbent, an oxygen absorber, or both. In this way, by incorporating a hygroscopic agent and / or oxygen absorber on the inner surface of the sealing plate, the effects of moisture and the like are eliminated as much as possible, and a long-life organic electrification port and luminescence element with little deterioration are provided. Obtainable.

The extraction electrode terminals of the transparent electrode layer and the metal electrode layer can be taken out of a joint between the sealing plate and the substrate that seals the light emitting layer. The circuit board can be directly connected to the terminal by taking out the terminal from the junction between the sealing plate and the substrate, and the drive IC that controls the electrode terminals and the organic electrifying port Electrically connected via the A drive circuit is connected to the organic electroluminescent port's luminescence element to function as a component for information display devices and lighting devices.

Furthermore, the method of manufacturing the organic electroluminescent device of the present Jg shell comprises a plastic layer in which a transparent layer, an organic electroluminescent port, a luminescent light emitting layer, and a metal electrode layer are sequentially laminated on a flexible plastic substrate. What is claimed is: 1. A method for manufacturing an organic electroluminescence element, wherein a surface of a substrate on which a light emitting layer is not formed is sealed with a sealing plate. The process is characterized in that the process up to bonding to the substrate is performed in an atmosphere of an inert gas such as nitrogen or in a vacuum.

In this way, the organic electrode port, the flexible plastic with a luminescent light emitting layer, and the plastic are sealed with a plastic substrate, and the entire process up to bonding is performed in an inert gas atmosphere such as nitrogen or in a vacuum. By doing so, a highly reliable organic EL device with little deterioration can be obtained. An information display device and a lighting device according to the present invention are any one of claims 1 to 8. It is formed by connecting a drive circuit and the like to the organic electret port and the luminescence element.

These components are not limited and can be combined as much as possible. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view of a configuration in which an organic electroluminescent device and a driving circuit according to an embodiment of the present invention are connected and can be used as an information display device or a lighting device.

FIG. 2 is a sectional view showing the structure of an organic electroluminescent device according to an embodiment of the present invention.

FIG. 3 is a view showing a flow of manufacturing an organic electroluminescent device according to an embodiment of the present invention. '

FIG. 4 is a schematic diagram of a mobile phone showing an example of the information display device.

FIGS. 5A and 5B are diagrams showing a method of filling an inert liquid between the flexible 'plastic' and the sealing plate.

FIG. 6 is a cross-sectional view of the configuration of the organic electroluminescent element of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Next, the organic electroluminescent (EL) element of the present invention will be described with reference to the drawings. The organic electroluminescence element of the present invention has a transparent electrode layer 11 on a flexible plastic substrate 10 as shown in FIG. A light-emitting layer 13 composed of an organic electorifice / noreluminescence and a metal layer 14 are sequentially laminated, and the light-emitting layer 13 is formed of a plastic with a sealing plate 15a on the non-display surface side (this embodiment). It is sealed. The surface of the substrate 10 on which the light emitting layer 13 is not formed is sealed with a sealing plate 15b on the display surface side made of plastic. Flexible plastic substrate 10 is a transparent or translucent and flexible substrate, and is made of plastic such as PC (polycarbonate), PET (polyethylene terephthalate) and PES (polyethersulfone). Material is used. As the substrate 10, PES or the like having particularly excellent heat resistance is preferable. On the upper surface of the plastic substrate 10, an organic layer including a transparent electrode 11, a hole transport layer 12, a light emitting layer 13 made of an organic EL material, and a metal electrode 14 are sequentially laminated. The organic EL element includes a plastic Si substrate 10, a transparent electrode 11 laminated on the upper surface thereof, a light emitting layer 13 made of at least an organic EL material, and a metal electrode 14.

The transparent electrode 11 has a function as a hole injection S¾, and has a structure in which light emitted from the light emitting layer 13 made of an organic EL material is extracted from a transparent or translucent plastic substrate 10. Ϊ change indium), IZO (zinc-de one flop indium _{oxide), ZnO, Sn0 2, I} n 2 0 3 or the like is used.

One has a single-layer structure of only the light-emitting layer 13 made of an organic EL material, and a two-layer structure of the hole-transport layer 12 and the light-emitting layer 13 or the light-emitting layer 13 and the electron-transport layer (not shown). Any structure such as a three-layer structure of the hole transport layer 12, the light emitting layer 13, 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 and the hole injection electrode 11 or the electron transport layer and the metal S 14 are stacked so as to be in contact with each other. When a hole injection layer, an electron injection layer, or the like is provided so as to be in contact with the hole injection 11 or the metal electrode 14, a four-layer structure, a five-layer structure, or a multilayer structure having more than four layers is used. There is also.

The light-emitting layer 13 is preferably made of a phosphor having a fluorescent property in the visible region and having good film-forming properties. In addition to Alq3 and Be-benzoquinolinol (BeBq2), 2,5-bis (5,7-di-t-pentyl-2-benzoxazolyl) ― 1,3,4-thiadiazol, 4,4,1-bis (5,7-bentyl-2-benzozoxazolyl) Stilbene, 4,4,1-bis [5,7-di- (2-methyl-1-butyl) -2-pentoxoxazolyl] stilbene, 2,5-bis (5,7-g-t-pentyl-2 —Benzoxazolyl) Thiophine, 2,5-bis ([5-hi, h-dimethylbenzyl] -1-2-benzoxazolyl) thiophene, 2,5-bis [5,7-di- (2 —Methyl-1-butyl) —2-Benzoxazolyl) —3,4-diphenylthiophene, 2,5-bis (5-methyl-1-benzobenzoxazo) Le) Chiofen, 4, 4, One-bis (2-pen Zoo according benzisoxazolyl) biphenyl, 5 - methyl-2- [2- [4 one (5-methyl-one 2-benzo O wherein benzisoxazolyl) phenylene Benzoxazolyl, 2- (2- (4-chlorophenyl) vinyl) naphtho [1,2-d] benzoxazoles such as oxazolyl, 2,2,1 (p —Phenylene divinylene) Benzothiazoles such as 1-benzobenzothiazole, 2- [2- (4- (2-benzimidazolyl) phenyl] vinyl] benzoimidazole, 2-C 2-(4-carboxy) Phenyl) vinyl] benzoimidazole-based fluorescent brighteners such as benzimidazole, etc., tris (8-quinolinol) aluminum dimethyl, bis (8-quinolinol) magnesium, bis (penzo [: f] 18-quinolinol) zinc, bis (2-methyl-18-quinolinolate) aluminum oxide, tris (8-quinolinol) indium, tris (5-methyl-8-quinolinol) aluminum , 8-quinolino-1-quinolinol, tris (5-1-quinolinol) gallium, bis (5-1-quinolinol) calcium, poly [zinc, bis (8-hydroxy-1-quinolinonyl) methane] 8-chelated xyquinoline-based metal complexes, such as metal-chelated oxinoid compounds such as dilithium epindridione, 1,4-bis (2-methylstyryl) benzene, and 1,4--1- (3-methylstyryl) Benzene, 1,4-bis (4-methylstyryl) benzene, distyrylbenzene, 1,4-bis (2-ethylstyryl) benzene, 1,4-bis (3-ethylstyryl) benzene, 1,4-bis (2- Styrylbenzene-based compounds such as 2-methylbenzene, 2,5-bis (4-methylstyryl) pyrazine, 2,5-bis (4- Rustyryl) pyrazine, 2,5-bis [2- (1-naphthyl) vinyl] pyrazine, 2,5-bis (4-methoxycistyryl) pyrazine, 2,5-bis [2- (4-biphenyl) vinyl] pyrazine 2,2,5-bis [2- (1-pyrenyl) vinyl] distilpyrazine derivative such as virazine, naphthylimide derivative, perylene derivative, oxaziazole derivative, aldazine derivative, cyclopentene derivative, A styrylamine derivative, a coumarin derivative, an aromatic dimethylidin derivative, or the like is used. In addition, anthracene, salicylate, pyrene, coronene and the like are also used.

The hole transport layer 12 is preferably a layer having a high hole mobility, being transparent and having good film formability. In addition to triphenylamine derivatives such as TPD, borfin, tetraphenylporphine copper, phthalocyanine, copper phthalocyanine , Titanium phthalocyanine Porphyrin compounds such as oxide, 1,1-bis {4_ (di-P-tolylamino) phenyl} cyclohexane, 4,4 ', 4''-trimethyltriphenylenamine, N, N, Ν ', Ν' —tetrakis (Ρ-tolyl) 10-phenylenediamine, 1- (Ν, Ν-di-tolylamino) naphthylene, 4, 4 '—bis (dimethylamino) 1 2_2' — dimethyl triphenylmethane, Ν, Ν, N ', Ν, - tetraphenyl one 4, 4 ⁵ - diamino Biff enyl, New, N' - diphenyl one New, New, temporary one m- tolyl one 4, N, N- Aromatic tertiary amines such as diphenyl, Ν ', bis (3-methylphenyl) -11, Γ-1,4,4'-diamine, 4'-diaminobiphenyl, Ν-phenylcarbazole, , 4-di-tolylaminostilbene, 4- (di-tolylamino) 1 4 '― [4- (di- Tolylamino) styryl] stilbene compounds such as stilbene, triazole derivatives, oxazizazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, anilineamine derivatives, amino Substituted chalcone derivatives, oxazolyl derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, silazane derivatives, polysilane-based arinline copolymers, high-molecular-weight oligomers, styrylamine compounds, and aromatics Organic materials such as dimethylidin-based compounds and poly 3-methylthiophene are used. Further, a polymer-dispersed hole transport layer in which a low molecular weight organic material for the hole transport layer 4 is dispersed in a polymer such as polycarbonate is used.

The electron transporting layer is composed of an osadiazol conductor such as 1,3-bis (4-tert-butyl-phenyl-1,3,4-oxaziazolyl) phenylene (OXD-7) or anthraquinodimethane Derivatives, diphenylquinone derivatives and the like are used. Examples of the metal electrode 14 include metals such as Al, In, Mg, and Ti; Mg alloys such as Mg—Ag alloys and Mg—In alloys; A 1—Li alloys; Al—Sr alloys; A1 alloy such as Ba alloy is used. In particular, A1-Mg alloy or A1-Li-Mg alloy is a metal having a low work function and excellent corrosion resistance, and is very effective.

Reference numerals 16a and 16b denote drive circuits, each of which includes a transparent electrode 11 of an organic EL element and a metal electrode. An IC for supplying a drive signal to the pole 14 is mounted. Circuit elements such as chip resistors and chip capacitors are arranged around the driving circuits 16a and 16b. 17 a and 17 b are terminals, which are connected to the transparent layer 11 and the metal layer 14. 18a and 18b are flexible circuit boards as external wiring, and electrically connect the electrode terminals 17a and 17b to the drive circuits 16a and 16b. Electric signals from the driving circuits 16a and 16b are supplied to the transparent electrode 11 and the metal electrode layer 14 via the external wirings 18a and 18b, and the light emitting layer 13 emits light according to the signal.

In the organic EL device sealed by the sealing plate 15a, the transparent ¾fil 1 and the metal SS14, which are formed above and below the light emitting layer 13, have the lead electrode terminals 17a and 17b of the S14 outside the bonding portions 19a and 19b. Have been withdrawn. The electrode terminals 17a and 17b are taken out of the joint between the sealing plate 15a and the flexible plastic substrate 10, and the circuit boards 16a and 16b are connected to the electrode terminals 17a and 17b. (2) The terminals 17 & and 17b and the driving IC for controlling the organic EL element are electrically connected via the circuit boards 18a and 18b.

By connecting the driving circuits 18a and 18b to the organic EL element, the above-mentioned light emitting layer 13 can emit light in accordance with a signal for each pixel, display a desired information image, and realize an information display device. Can be configured. By forming each pixel of the light emitting layer 13 with R, G, and B, an information image can be displayed in full color. For example, as shown in FIG. 4, the information display unit 9 of the mobile phone can be configured, or an electronic organizer or the like can be configured. Furthermore, by turning on or off the whole without displaying an image, it can also function as a part for a lighting device.

In the present invention, in order to protect the light emitting layer 13 (light emitting portion including other organic layers and both electrodes) and prevent water from entering, the light emitting layer 13 is placed on the organic layer side (the non-display surface side in this embodiment). The structure of sealing with the sealing plate 15a is adopted. A sealing plate 15a for sealing the surface on which the light emitting layer 13 is formed and the non-display surface side in the embodiment of the present invention includes a flexible (PC) (polycarbonate) having the same flexibility as the plastic substrate 10. , PET (polyethylene terephthalate) and PE (polyethylene), PP Materials such as (polypropylene) are used, but PP and PC, which have particularly low hygroscopicity (absorption rate), are excellent.

The feature of the present application is that the surface on which the light emitting layer 13 is not formed, and the display surface side in the embodiment of the present invention are sealed with a sealing plate 15b made of a plastic material, so that moisture and oxygen permeability are high. Even in the case of an organic EL device using the flexible plastic substrate 10, it is possible to prevent the device light emission performance from deteriorating due to moisture or oxygen entering from the outside. As a result, it is possible to provide a flexible organic EL device having a practical long life. Similar to the sealing plate 15a, materials such as PC (polycarbonate), PET (polyethylene terephthalate), PE (polyethylene), and PP (polypropylene) are used for the sealing plate 15b. In order to suppress the diffusion of oxygen and moisture into the inside, a material having a small absorption rate or a material having high heat resistance is preferable, and a plurality of sealing plates are used depending on the material used.

In this embodiment, two sealing plates 15a and 15b are used on both sides of the substrate 10, and the flexible plastic substrate 10 is sandwiched and sealed, but one sheet is folded. The same effect can also be obtained by sealing the display surface side and the non-display surface side of the flexible 'plastic substrate 10 using two substrates apparently as described above.

The sealing plate 15a made of a plastic material for sealing the non-display surface has transparency enough to cure the ultraviolet curing resin with respect to ultraviolet light having a wavelength of about 30 O nm. A resin having an ultraviolet ray composition is applied to the joint 19 a between the sealing plate 15 a and the flexible plastic substrate 10, and ultraviolet rays are irradiated from the sealing plate side 15 a without a mask, thereby forming the sealing plate. 15a and flexible plastic substrate 10 can be bonded. The sealing plate 15b used for sealing the display surface side has a light transmitting property so that light from the light emitting layer 13 can be extracted. Utilizing this property, an ultraviolet curing resin is applied to the joint 19b between the sealing plate 15b and the flexiplastic plastic substrate 10 and the sealing plate 15b is irradiated with ultraviolet light to seal. The stop plate 15b and the flexible 'plastic substrate 10 can be bonded.

In this method, the bonding between the sealing plates 15a and 15b and the flexible plastic substrate 10 can be performed at a low temperature of 100 ° C or less, so that PET (Poly-Poly) is particularly low in heat resistance. This is particularly effective when a material such as ethylene terephthalate) is used for the flexible plastic substrate 10.

By bonding the sealing plates 15a and 15b and the flexible plastic resin 10 with a thermosetting resin, an organic EL device with low moisture and oxygen permeability and high reliability and long life can be obtained. be able to. Conventional organic EL devices using glass have high thermal conductivity, so when bonding with a thermosetting resin, the heat applied to cure the resin emits light from the organic EL through a glass substrate with high thermal conductivity. In some cases, the light-emitting layer exceeded the glass transition temperature, causing crystallization of organic substances and the like, and the light-emitting characteristics of the device were rapidly deteriorated.

However, when PES (polyethersulfone) or the like having relatively high heat resistance is used for the plastic flexible substrate 10, since the thermal conductivity is lower than that of glass, the light-emitting layer 13 made of heat-sensitive organic EL is used. The plastic flexible 10 can be bonded to the sealing plate 15a without any influence. In other words, a thermosetting resin is applied to the joints 19a and 19b between the sealing plates 15a and 15b and the plastic / flexible substrate 10 and locally heated only at the joints 19. In addition, since the plastic and flexible substrate 10 has lower thermal conductivity than glass, heat is hardly transmitted to the light emitting layer 13. In particular, this bonding method is the most reliable bonding method because the heat-cured resin has low moisture permeability and oxygen permeability, and a highly reliable organic EL device can be obtained.

The two-component epoxy resin that starts curing by mixing the main agent and the curing agent is applied to the joints 19 & and 19 b, and is hardened to form the sealing plates 15 & and 15 b. Flexible · Plastic substrate 10 can be bonded. This method allows bonding at room temperature. This is particularly effective when a material such as PET (polyethylene terephthalate) having low heat resistance is used for the flexible plastic substrate 10. In addition, as a two-component epoxy resin, for example, a curing reaction such as a tertiary amine or a catalyst type, a polyaddition type, or a latent type is added to an epoxy resin as a base material to cause a chain reaction, thereby causing a hardening reaction. What can be used can be used. Either one or both of the inner surface of the sealing plate 15a and the inner surface of the sealing plate 15b is coated with silicon or metal oxide film and nitride film, or a laminate thereof by a method such as a vacuum evaporation method. It is preferable to form a gas barrier layer (not shown) in which a metal film such as aluminum and a metal film such as aluminum is laminated. By forming the gas barrier layer on the sealing plates 15 & and 15 b, it is possible to further prevent the infiltration of moisture and to obtain a long-life organic EL device. Further, a gas barrier layer (not shown) can be formed on the flexible plastic substrate 10 to further improve the moisture resistance. In this case, it is provided between the transparent SMI 1 and the flexible plastic substrate 10, or between the flexible plastic substrate 10 and the sealing plate 15b.

When an aluminum film gas barrier layer is laminated on the sealing plate 15a, it becomes opaque to ultraviolet rays. In this case, it is possible to remove the aluminum film only at the joint 19a, apply an ultraviolet-curing resin to the joint 19a, irradiate ultraviolet rays to irradiate the resin, and bond the resin. it can.

Note that the sealing plate 15b on the display surface side must be formed with a gas barrier layer that is not opaque to light so that light can be extracted from the light emitting layer 13.

Even when a film opaque to ultraviolet rays such as an aluminum film is deposited on the inner surface of the sealing plate 15a, a thermosetting resin may be applied to the joint 19a to apply heat, By applying the epoxy resin, the sealing plate 15a and the flexible plastic substrate can be bonded. In any case, it can be carried out in an atmosphere of an inert gas such as nitrogen or in a vacuum.

Adhesion between the sealing plates 15a and 15b and the flexible 'plastic' 10 is realized by appropriately combining the above methods according to the material used.

Next, a plastic material suitable for the present invention was examined. Table 1 shows the physical properties of various plastic film materials. The table compares various physical properties of soda glass and various plastic film materials. Glass has a large specific gravity and is heavy, but has low water absorption and excellent heat resistance. That is, the glass transition point is high and the coefficient of linear expansion is small.

Plastic materials have low specific gravity and light weight, but have high water absorption and poor heat resistance. That is, they have a low glass transition point and a large coefficient of linear expansion. Glass and plastic show almost the same value in total light transmittance and refractive index, and can be optically used for the same purpose. Among plastic materials, PP (polypropylene) is the best in terms of water absorption and heat resistance. Water-absorption is extremely high, but the glass transition point is extremely low, and it is not suitable as organic EL device substrate 10. In terms of heat resistance, PES (polyethersulfone) has the highest glass transition point and low linear expansion coefficient, so it is suitable for organic EL element substrates, but it is not suitable for sealing plates because of its high water absorption. For the sealing plates 15 & 15b, PP (polypropylene) or PC (polycarbonate) with a relatively low water absorption is suitable. Apart from the water absorption of the material, there is a method of forming a gas barrier layer on the inner surface of the sealing plate or laminating a metal film such as an aluminum foil to reduce the moisture permeability.

Table 1 Properties of various plastic film materials (including soda glass)

Explanation of symbols in the table: PG (Polycarbonate), PET (Polyethylene f phthalate), PP (Polypropylene), PES (Polyethyl sulfone: ^), PSF (Polysulfone), PAR (Polyarylate), PMMA (Polymethylenmethacrylate) (Crylate) Table 2 shows a comparison between the effects of the prior art and the present invention. Table 2 shows the most basic conventional example as Conventional 1.In Conventional 1, soda glass is used for the organic EL element substrate and the sealing plate. Can be applied. Due to the fact that oxygen permeability and moisture permeability are so small as to be negligible compared to plastics, this is the configuration with the least deterioration of the element. However, if flexibility is required for organic EL devices in the future, glass is not suitable.

In addition, as shown in Conventional 2 and Conventional 3, when a glass substrate is simply replaced with a flexible plastic substrate, the organic EL element is significantly deteriorated and practical use is difficult. 2003/008889

1 6

According to the present invention, in the organic EL element using a flexible plastic material, the flexible organic EL element is practically reliable by adopting a structure in which the light emitting display surface side of the flexible plastic is sealed with a plastic sealing plate. Gender level.

As a method of the present invention, a method of using a plurality of sealing plates, providing a bonding method according to the heat resistance of each plastic material, and providing a substrate of an organic EL element, a display surface side sealing plate and a non-display surface side Oxygen permeability and moisture permeability were structurally suppressed by providing a gas barrier layer suitable for the sealing plate.

The principle of the present invention is to block the organic EL element with a plurality of blocking layers (sealing plate and organic EL element E) from oxygen and moisture in the air to reduce the diffusion speed. The diffusion rate (diffusion coefficient) of oxygen and moisture in a solid from a gas and in a solid is governed by its concentration difference (partial pressure difference), pressure and temperature.

However, since pressure and temperature are common items, the difference in concentration, that is, the difference in partial pressure of oxygen and moisture in gas poses a problem. Oxygen and water molecules enter the sealing plate from the air according to temperature and pressure and diffuse according to the diffusion coefficient of each plastic material.

In the case of the conventional organic EL device on a flexible plastic substrate, molecules of oxygen and water enter the organic EL device and deteriorate the device. In the present invention, the diffusion of oxygen and moisture into the inside can be suppressed stepwise by the plastic sealing plate, and the time to reach the organic EL device can be delayed. Therefore, the amount of oxygen and water in the organic EL element decreases, and the deterioration of the element is suppressed. Degradation of luminance in the degradation item (entire surface of the light-emitting portion) refers to a case where moisture or oxygen passes through the sealing plates 15a and 15b, and the luminance of the light-emitting layer 13 is degraded by moisture or oxygen. Luminance deterioration (around the light-emitting portion) refers to a case where the light-emitting layer 13 deteriorates in luminance due to a gas generated from a resist formed in the manufacturing process of the organic EL device. To prevent this, it is necessary to apply heat to the resist to evaporate gases such as moisture.The more heat-resistant substrates are used, the greater the amount of heat applied, and the greater the effect 7 Table 2 Differences in the degree of deterioration of the organic EL device depending on the substrate material

Explanation of symbols in the table: PET (polyethylene ^ phthalate), PC (polycarbonate), PES (polyethylene sulfone), PE (polyethylene)

Display side / rear layer (laminated film of silicon oxide film, silicon oxynitride film, aluminum oxide film, etc.) Organic EL device substrate / rear layer (silicon oxide film, silicon oxynitride film, aluminum oxide film, etc.) Non-display surface side barrier layer (Laminated film of silicon oxide film, silicon oxynitride film, aluminum film, etc.)

PE / Aluminum foil PE (Aluminum foil laminated with polyethylene film)

FIG. 2 is a schematic view of an organic EL device illustrating another embodiment of the present invention. In FIG. 2, 25a and 25b are sealing plates made of a plastic material such as PC (polycarbonate) and TAC (triacetylcellulose). A hard coat film (not shown) made of acryl resin is applied to the surfaces of the sealing plates 25a and 25b to prevent damage due to external factors.

On the inner surfaces of the sealing plates 25a and 25b, aluminum vapor-deposited films, silicon oxide films or silicon oxynitride films are sequentially laminated (not shown) in the order of several tens to several hundreds of nm each. It prevents moisture and oxygen from entering from outside. However, an aluminum vapor-deposited film is not applied to the sealing plate 25a on the display surface side so as not to be opaque.

Reference numeral 20 denotes a plastic substrate as a transparent substrate, which includes PC (polycarbonate), PET (polyethylene terephthalate), and PES (polyethersulfur). On) Use a transparent resin film with a thickness of about 50 to 300〃m. On the upper surface of the plastic substrate 20, a transparent electrode 21, a hole transport layer 22, a light emitting layer 23 made of organic EL, a metal electrode 24, and a vapor-deposited film of calcium or the like as a moisture absorbing layer (not shown) A silicon oxynitride vapor-deposited film (not shown) as a barrier layer for a gas of moisture and oxygen is sequentially laminated. A silicone oil or a carbon fluoride-based inert liquid 26 b is filled between the display surface side sealing plate 25 b and the plastic substrate 20 c. Liquid 26b is a liquid that is thermally stable and highly non-flammable (has no flash point), non-toxic, odorless, metal and plastic, and other organic electrified ports and luminescent elements. It does not corrode the constituent materials, has high electrical insulation (10 KV or more per 2.54 mm GAP), and has excellent permeability (surface tension of 3 O mN / m (25 ° C) or less) , Good thermal conductivity (thermal conductivity 15 W / m-K or more), small change in viscosity (pour point-40 ° C or less), high boiling point (150 ° C or more), ozone destruction coefficient Refers to a zero liquid.

Examples of the silicone oil include dimethyl silicone oil used as an insulating oil for transformers, and methylphenyl silicone oil used as a heat carrier. In addition, as a fluorine-based inert liquid, there is a carbon fluoride-based inert liquid such as Fluorinert (trade name) developed by Threem Corporation in the United States.

By filling with silicone oil or a carbon fluoride inert liquid 26 b, it is possible to suppress a decrease in external extraction efficiency due to light scattering and promote heat radiation from the light emitting layer 23 made of organic EL. In order to enclose the inert liquid, for example, as shown in FIG. 5A, the inert liquid 5 is dropped into the concave portion of the sealing plate 15a, and the adhesive 4 described above is applied around the inert liquid. Then, as shown in FIG. 5B, a flexible plastic substrate 10 on which the transparent electrode layer 11, the light emitting layer 13, the metal layer 14, and the like are formed is covered and adhered. Can be

In addition, the space between the non-display surface side sealing plate 25a and the gas barrier layer on the surface of the organic EL element is filled with the inert liquid 26a in the same manner as described above, so that the light emitting layer 23 made of organic EL is formed. Promotes heat dissipation, and protects the organic EL element by dispersing external mechanical stress in the liquid. 27 a and 27 b are electrode terminals for connecting external wiring.

In addition, the periphery of the display surface side sealing plate 25 b and the periphery of the plastic substrate 20 and the The display surface side sealing plate 25a and the plastic substrate 20 are bonded to the joints 29a and 29 by applying a thermosetting resin and curing by thermocompression bonding, or by applying an ultraviolet curable resin to the joining portions 29a and 29b. Is applied and cured by UV irradiation. In either case, it may be performed in an atmosphere of an inert gas such as nitrogen or in a vacuum.

FIG. 3 is a flow chart of manufacturing an organic EL device according to an embodiment of the present invention. In FIG. 3, a transparent conductive film 2 made of ITO is previously formed on a flexible plastic substrate 10 by a sputtering method or an ion plating method, and a resist film 1 is formed on the surface of the ITO transparent conductive film. To form a photoresist pattern by photolithography (S1) o Flexible plastic substrate 10, such as PC (polycarbonate), PET (polyethylene terephthalate), and PES (polyester sulfone) Plastic material is used.

Next, in the case of a polycrystalline IT0 film, use an aqueous solution of a mixture of hydrochloric acid and ferric chloride or an aqueous solution of hydrochloric acid and a nitric acid. In the case of an amorphous ITO film, use an aqueous solution of an organic acid such as citric acid or a dilute hydrochloric acid. Photo-etching of the ITO transparent conductive film with a nitric acid solution is performed, and then the unnecessary photoresist is removed with an organic solvent such as acetone or an aqueous solution of potassium hydroxide. The formation of 11 is completed (S2).

Next, a photoresist to be an insulating film is applied on the plastic substrate 10 and pre-baked, and then exposed and developed by a photolithography method to form an insulating film pattern 3 (S3). Furthermore, the flexible plastic substrate 10 on which the hole injection electrode 11 and the insulating film pattern 3 are formed is baked at as high a temperature as possible, depending on the heat resistance of the substrate 10, to adversely affect the light emitting layer 13 made of organic EL. The organic solvent component remaining in the insulating film 3 and the moisture adsorbed on the surface are evaporated. Next, the hole transport layer 12, the light emitting layer 13, and the electron injection metal electrode 14 are sequentially formed by a vacuum evaporation method (S4 to S6). The hole transport layer 12 and the light emitting layer 13, at 10 one ⁴ Pa order of about a clean vacuum, and vacuum evaporation using resistance heating evaporation source. Electron injection metal No. 14 was prepared using a BN (boron nitride) boat in the same vacuum as above. The film is formed by thermal evaporation or EB evaporation using an EB (electron beam) gun. Since the light-emitting layer 13 has different dyes for doping depending on the emission color, in an organic EL device that emits light of a plurality of colors, the emission color is separately applied to each emission color by a mask vapor deposition method using a metal mask. Similarly, the electron-injection metal electrode 14 is separately coated by a mask vapor deposition method using a metal mask according to the light emission pattern.

Finally, a seal-bonding date 4 is applied and drawn around the sealing plates 15a and 15b made of plastic by a dispenser or screen printing. Next, sealing plates 15a and 15b are occupied on the display surface side and the non-display surface side of the organic EL element by ultraviolet irradiation, heating, or permanent depending on the type of sealing resin. Then, the sealing adhesive resin 4 is hardened to complete the sealing (S7). Thus, the organic EL device of the present invention is completed.

In the above description, a method of manufacturing one organic EL element is described for convenience. However, in practice, a flexible plastic substrate of the organic EL element and a plastic substrate serving as a sealing plate are large and can be formed into multiple sheets. It is possible to use a sheet-shaped or roll-shaped plastic substrate. 1 and 2, the illustration of the patterning of the transparent electrode 11 and the insulating film 3 is omitted.

In this case, the sealing plate is attached to the display surface side and the non-display surface side of the organic EL element in an inert atmosphere such as nitrogen or in a vacuum, and the sealing resin is cured so that the area around the light emitting layer is inactive. It can be in a gas or vacuum atmosphere, can be isolated from oxygen and moisture, and can prevent the ingress of moisture from the outside by the sealing plate. A highly reliable organic EL device can be obtained. In this case, after sealing, take out into the atmosphere and cut each organic EL element into single pieces (cut off all plastic boards), and cut to remove unnecessary plastic boards on the terminals (peripheral removal) Only the sealing plate on the terminal section is cut off), and the step is performed.

ADVANTAGE OF THE INVENTION According to this invention, in the flexible organic EL element using a plastic reaction, oxygen and moisture which permeate | transmit and diffuse in the whole plastic substrate from the outside can be suppressed, and the growth of a dark spot and the fall of brightness | luminance can be prevented. Industrial applicability

According to the present invention, it is possible to extend the life with little change over time and to use various display devices with high practicality that can be used in an operating environment requiring high reliability, such as mobile phones, mobile terminals, and electronic notebooks. ^ It can be used for belt-type display devices, and even lighting devices.

Claims

Scope of Word

1 A transparent electrode layer, a light-emitting layer composed of electro-luminescence, and a metal electrode layer are sequentially laminated on a flexible plastic substrate, and an organic electrifying port is formed by sealing the light-emitting layer with a sealing plate composed of a plastic. -An organic electroluminescent element, wherein the surface on which the light emitting layer is not formed is sealed with a sealing plate made of plastic.

2. The organic electroluminescence according to claim 1, wherein at least one of a sealing plate for sealing the light emitting layer or a sealing plate for sealing a substrate is bonded to the substrate with an ultraviolet curable resin. element.

3. The organic electing device according to claim 1, wherein at least one of a sealing plate for sealing the light emitting layer or a sealing plate for sealing a substrate is bonded to the substrate with a thermosetting resin. Mouth 'no luminescence element.

(4) At least one of a sealing plate for sealing the light-emitting layer or a sealing plate for sealing a substrate is bonded to an epoxy resin which starts curing by mixing a base material and a curing agent. The organic electroluminescent element according to claim 1, wherein

5. The organic electroluminescence according to claim 1, wherein a gas barrier layer is formed on one or both of an inner surface of a sealing plate for sealing the light emitting layer and an inner surface of a sealing plate for sealing the substrate. element.

6 One or both of a sealing plate for sealing the light emitting layer and the substrate, or a sealing plate for sealing the substrate and a space formed by the substrate, or a silicone oil-based or fluorine-based material 2. The organic electroluminescence port / noreluminescence device according to claim 1, wherein the organic electroluminescence device is filled with an inert liquid.

(7) One or both of the inner surface of the sealing plate for sealing the light emitting layer and the inner surface of the sealing plate for sealing the substrate contains a moisture absorbent, an oxygen absorber, or both. 2. The organic electroluminescence device according to claim 1, wherein

8. The organic device according to claim 1, wherein the extraction electrodes of the transparent electrode layer and the metal electrode layer are taken out of a junction between a sealing plate for sealing the light emitting layer and a substrate. Select port 'Luminescence element. 9 Flexible / plastic plastics, a transparent electrode layer, an organic electroluminescent port, a luminescent layer, and a metal layer are sequentially laminated and sealed with a plastic sealing plate. Wherein the surface of the substrate on which the light emitting layer and the light emitting layer are not formed is sealed with a sealing plate, and the step of bonding the sealing plate to the substrate is performed in an inert gas atmosphere such as nitrogen, or A method for manufacturing an organic electroluminescent device, which is performed in a vacuum.

10. An information display device or a lighting device, comprising the organic electroluminescent element according to claim 3 according to claim 1.