JP2002093574A - Electroluminescence device and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an EL device and its manufacturing method which can prevent moisture from the outside and inhibit degradation of the EL device over a long period of time by sealing the EL device with a glass substrate and a damp-proof film after producing the EL device by film rolling, and to provide the cheap EL device and its manufacturing method by raising its productivity. SOLUTION: In the electroluminescence device which is laminated to one side surface of a plastics base material 1 one by one with at least, a transparent anode layer 2, a luminescence medium layer 3, and a cathode layer 4, and the above laminated body is covered and sealed with a damp-proof film, a glass substrate 5 is laminated in the other side surface of the above plastics base body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent device (hereinafter, referred to as an EL device) which is expected to be widely used as a display for an information display terminal or a surface emitting light source.

[0002]

2. Description of the Related Art EL elements are expected to be used as flat panel displays in place of cathode ray tubes and liquid crystal displays because of their advantages such as a wide viewing angle, a high response speed, and low power consumption.

An EL element has a structure in which an organic or inorganic luminescent medium layer is sandwiched between two electrodes, at least one of which is transparent. Light is generated in the luminescent medium layer by applying a voltage between the two electrodes. (Hereinafter, an example in which a voltage is applied to the organic light emitting medium layer will be described).

When the EL element is left in a state where the light emitting medium layer and the cathode layer are exposed to the air, the EL element is deteriorated by moisture and oxygen in the air. As one specific example, there is a phenomenon that a non-light-emitting area called a dark spot occurs and expands with time.

As a method for solving this problem, Japanese Patent Application Laid-Open
JP-A-182759 and JP-A-5-36475. In these, a luminescent medium layer and a cathode layer are continuously formed under vacuum on a glass substrate on which a transparent anode layer is formed, and EL is dried under a dry nitrogen atmosphere using a metal or glass sealing can.
This is a method of covering and sealing the element.

However, in order to manufacture such an EL element, a plurality of vacuum deposition apparatuses capable of transporting a glass substrate under vacuum and a sealing apparatus under nitrogen are required, so that productivity is low and manufacturing cost is low. There was a problem such as high. In addition, since a glass substrate or a metal sealing can is used, there is a limit in reducing the thickness and weight of the element.

As a means for solving this problem, there has been proposed a method in which a light-emitting medium layer and a cathode layer are wound on a plastic film by a vapor deposition method or a printing method, and the EL element is covered and sealed with a moisture-resistant film. Have been. This allows
A thin and lightweight EL element can be manufactured at low cost.

Since the moisture-resistant film is disposed on the side opposite to the EL light extraction surface, it does not need to be translucent, and a moisture-resistant film made of a metal foil having particularly excellent moisture resistance can be used. On the other hand, since the plastic film on the EL light extraction surface side is required to have moisture resistance and translucency,
A technique of depositing a transparent inorganic thin film on a plastic film or laminating a transparent inorganic thin film deposited film has been adopted. However, the current transparent inorganic thin film deposition film cannot suppress the deterioration of the EL element for a long time.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method of manufacturing an EL device by winding a film, and then forming an EL element on the glass substrate. An object of the present invention is to provide an inexpensive EL element and a method of manufacturing the same by sealing the film with a conductive film, which can block moisture from the outside, suppress deterioration of the EL element for a long period of time, and improve productivity.

[0010]

In order to solve the above-mentioned problems, according to the present invention, at least a transparent anode layer, a luminescent medium layer, and a cathode layer are sequentially laminated on one surface of a plastic substrate. An electroluminescent device comprising the laminate laminated and covered with a moisture-resistant film, wherein a glass substrate is laminated on the other surface of the plastic substrate. Further, in claim 2, the glass substrate has a take-out electrode on a surface in contact with the plastic base material, and the take-out electrode is electrically connected to the transparent anode layer and the cathode layer. An electroluminescent device according to claim 1, wherein According to a third aspect of the present invention, in the electroluminescent device according to the first or second aspect, the moisture-resistant film is thermocompression-bonded to the glass substrate. Further, in claim 4, a step of sequentially laminating at least a transparent anode layer, a luminescent medium layer, and a cathode layer on one surface of a plastic substrate, a step of forming an extraction electrode on a glass substrate, Laminating on the other side of the material,
Electrically connecting the extraction electrode to the transparent anode layer and the cathode layer, and at least covering and sealing by thermocompression bonding the glass substrate and the moisture-resistant film on which the extraction electrode is formed. This is a method for manufacturing an electroluminescence element.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of an EL device of the present invention and a manufacturing process thereof will be described with reference to FIG.

In this embodiment, the plastic substrate 1 may be a stretched or unstretched film made of polyethylene terephthalate, polypropylene, polyether sulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, or the like. Sheets can be used. Before forming a transparent anode layer on these plastic films, a surface treatment such as a corona treatment, a plasma treatment, or a UV ozone treatment may be performed.

First, a transparent anode layer 2 is wound on a plastic substrate 1 by a sputtering method or a vacuum evaporation method to form a film. Then, the transparent anode layer 2 is transparently wound on the film by a photolithography method and a wet etching method. The anode layer is patterned to form a transparent anode layer 2 also serving as an anode extraction electrode 2a and a cathode extraction electrode 2b. Alternatively, the transparent anode layer may be patterned by mask evaporation.

As a material of the transparent anode layer 2 in the present invention, ITO (indium tin composite oxide), indium zinc composite oxide, zinc aluminum composite oxide and the like can be used. In addition, in order to reduce the wiring resistance of the transparent anode layer, a metal material such as copper or aluminum may be provided as an auxiliary electrode in addition to the transparent anode layer.

Next, the light emitting medium layer 3 is wound on the transparent anode layer 2 to form a film. The light emitting medium layer 3 in the present invention can be formed of a single layer film containing a fluorescent substance or a multilayer film. When the light-emitting medium layer is formed of a multilayer film, examples of the structure of the light-emitting medium layer include a hole transport layer, an electron-transport light-emitting layer or a two-layer structure including a hole-transport light-emitting layer, and an electron-transport layer. There is a three-layer configuration including a transport layer. Further, it is also possible to form a multi-layer, and each layer is sequentially formed on a substrate.

Examples of the hole transport material include metal phthalocyanines such as copper phthalocyanine and tetra (t-butyl) copper phthalocyanine, and metal-free phthalocyanines, quinacridone compounds, 1,1-bis (4-di-p-tolyl). Aminophenyl) cyclohexane, N, N'-diphenyl-
N, N'-bis (3-methylphenyl) -1,1'-biphenyl-4,4'-diamine, N, N'-di (1-naphthyl) -N, N'-diphenyl-1,1 ' It can be selected from low molecular materials such as aromatic amines such as -biphenyl-4,4'-diamine, high molecular materials such as polythiophene and polyaniline, polythiophene oligomer materials, and other existing hole transport materials.

Examples of the light emitting material include 9,10-diarylanthracene derivatives, pyrene, coronene, perylene, rubrene, 1,1,4,4-tetraphenylbutadiene, tris (8-quinolinolato) aluminum complex, tris (4 -Methyl-8-quinolinolate) aluminum complex, bis (8-quinolinolate) zinc complex, tris (4-methyl-5-trifluoromethyl-8-quinolinolate) aluminum complex, tris (4-methyl-
5-cyano-8-quinolinolate) aluminum complex,
Bis (2-methyl-5-trifluoromethyl-8-quinolinolate) [4- (4-cyanophenyl) phenolate] aluminum complex, bis (2-methyl-5-cyano-8-quinolinolate) [4- (4- Cyanophenyl)
Phenolate] aluminum complex, tris (8-quinolinolate) scandium complex, bis [8- (para-tosyl) aminoquinoline] zinc complex and cadmium complex,
1,2,3,4-tetraphenylcyclopentadiene,
Pentaphenylcyclopentadiene, poly-2,5-diheptyloxy-para-phenylenevinylene, coumarin-based phosphor, perylene-based phosphor, pyran-based phosphor, anthrone-based phosphor, porphyrin-based phosphor, quinacridone-based phosphor, Low molecular materials such as N, N'-dialkyl-substituted quinacridone-based phosphors, naphthalimide-based phosphors, N, N'-diaryl-substituted pyrrolopyrrole-based phosphors, and polymers such as polyfluorene, polyparaphenylenevinylene, and polythiophene Materials and other existing light emitting materials can be used.

Examples of the electron transporting material include 2- (4-bifinylyl) -5- (4-t-butylphenyl)-
1,3,4-oxadiazole, 2,5-bis (1-naphthyl) -1,3,4-oxadiazole, oxadiazole derivatives and bis (10-hydroxybenzo [h] quinolinolate) beryllium complex And triazole compounds.

As a method of forming the light emitting medium layer 3, in the case of a low molecular material, a film can be formed by winding by a vacuum evaporation method such as a resistance heating method. In the case of a polymer material, the film can be formed by winding using a wet coating method such as flexo, gravure, microgravure, gravure offset, die coating, intaglio offset, and roll coating. The thickness of the light-emitting medium layer is 1000 nm or less, preferably 50 to 150 nm, even when it is formed as a single layer or a stacked layer.

Next, the cathode layer 4 is formed on the light emitting medium layer 3. As the material of the cathode layer 4, a substance having a high electron injection efficiency is used. Specifically, a simple metal such as Mg, Al, or Yb may be used, or Li or oxidized L
Al and Cu having high stability and conductivity are laminated and used with a compound such as i, LiF or the like sandwiched by about 1 nm.

Alternatively, in order to achieve both electron injection efficiency and stability, Li, Mg, Ca, Sr, La, and
An alloy system of one or more metals such as Ce, Er, Eu, Sc, Y, and Yb and stable metal elements such as Ag, Al, and Cu is used. Specifically, MgAg, AlLi, CuLi
And other alloys can be used.

As a method for forming the cathode layer 4, depending on the material, a film can be formed by winding using a resistance heating evaporation method, an electron beam evaporation method, a reactive evaporation method, an ion plating method, a sputtering method, or the like. It is possible. Further, it is also possible to laminate a metal foil such as an aluminum foil by laminating the light emitting medium layer 3 formed on the plastic substrate 1, passing between rolls and thermocompression bonding.
The thickness of the cathode when the film is formed by winding is 10 nm to 10 nm.
About 00 nm is desirable. When the metal foil is laminated, the thickness is desirably 5 μm or more, which is easy to handle, and more preferably, 15 μm or more to prevent pinholes in the foil. Further, in order to further facilitate the handling, a plastic film such as polyethylene terephthalate may be laminated on the metal foil in advance on the surface opposite to the surface in contact with the EL element.

Next, on the glass substrate 5 (the surface in contact with the plastic substrate), an anode extraction electrode 6 for powering the EL element is provided.
a and the cathode extraction electrode 6b. Materials for the extraction electrode include metal materials such as aluminum, copper, silver, nickel, and chromium, or alloy materials containing at least one of these metal materials, indium tin composite oxide, indium zinc composite oxide, and zinc aluminum composite oxide. Metal oxides such as substances can be used alone or in combination. Further, a color filter may be formed on the glass substrate 5 and used as a color filter having an extraction electrode.

As a method of forming the extraction electrodes 6a and 6b, a resistance heating evaporation method, an electron beam evaporation method, a reactive evaporation method, an ion plating method, a sputtering method, or the like can be used depending on the material. Further, it is preferable to perform masking at the time of forming the film or to process the film into a predetermined pattern by using a photolithography / etching method, a dry etching method, or the like after the film is formed.

Next, the glass substrate 5 on which the extraction electrodes 6a and 6b are formed is laminated on the plastic substrate 1, and the anode extraction electrode 6a and the cathode extraction electrode 6b on the glass substrate are formed.
Are electrically connected to the anode extraction electrode 2a and the cathode extraction electrode 2b of the EL element via the conductive material 7, respectively. At this time, the glass substrate 5 and the plastic substrate 1
At the same time as the electrical connection by the conductive material 7, the adhesive is fixed. In addition, in order to adhere and fix more firmly, UV curable adhesive resin or electron beam curable adhesive resin is applied to the interlayer or between the glass substrate and the plastic substrate, and then reinforced by curing. May be.

As the conductive material 7, Au, Ag, C
metal particles such as u, Al, Ni, etc., SnO ₂ , In ₂ O
Conductive resin materials mainly composed of conductive fine particles such as oxide fine particles and carbon fine particles such as ₃ and binder resins such as polyester resin, acrylic resin, modified urethane resin and epoxy resin, aluminum, copper, silver, etc. Metal materials, alloy materials composed of tin, lead, silver, etc., and Sn
Metal oxides such as O ₂ and In ₂ O ₃ can be used alone or in combination. In particular, the film substrate and the glass substrate can be easily bonded and fixed,
It is desirable to use at least a conductive resin material that can be molded at a low temperature.

Depending on the material, the conductive material 7 may be formed by a coating method such as a nozzle discharge method or a screen printing method, a film forming method such as a vapor deposition method or a sputtering method, a thermocompression bonding method, a soldering method, or the like. Etc. can be used. For example, in the case of a paste-like conductive resin material, it can be formed by a screen printing method or the like. In the case of a film electrode made of a metal material, it can be bonded by thermocompression bonding via a film-shaped conductive resin material.

Finally, in order to shut off moisture from the outside and suppress deterioration of the EL element for a long period of time, the EL element is covered and sealed by thermocompression bonding of a moisture-resistant film 8.
When performing thermocompression bonding, the end of the moisture-resistant film may be thermocompression-bonded, or the entire moisture-resistant film may be thermocompression-bonded by passing between heat rolls.

The moisture-resistant film 8 needs to have at least a barrier layer and a sealant layer. As the barrier layer, silicon oxide, aluminum oxide, chromium oxide,
Metal oxides such as magnesium oxide, aluminum fluoride,
A film in which metal fluorides such as magnesium fluoride, metal nitrides such as silicon nitride, aluminum nitride, and chromium nitride are single-layered or laminated; a film in which aluminum, copper, nickel, stainless steel, an aluminum alloy, or the like is deposited;
Metal foils and alloy foils of these materials can be used. In particular, it is preferable to use a metal foil or an alloy foil having excellent gas barrier properties. In addition, a film such as polyethylene terephthalate or nylon may be laminated as a base material in order to facilitate handling during manufacture.

As the sealant layer, acid modified products of polyolefins such as polyethylene, polypropylene, ethylene / propylene copolymer, acid modified products of ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / methacrylic acid Thermoplastic adhesive resins such as copolymers and ionomers can be used.

The place where the moisture-resistant film 8 is thermocompression-bonded is preferably made with the glass substrate 5 rather than with the plastic substrate 1. The reason for this is that when thermocompression bonding is performed on the plastic substrate 1, moisture penetrates from the end of the plastic substrate 1 and the element is deteriorated, and the bonding strength with the glass substrate is higher than that of the plastic substrate. And that the film strength of a transparent anode layer formed on a plastic substrate is lower than that of a glass substrate.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an EL device according to the present invention and a method for manufacturing the same will be described. FIG. 1 is an explanatory sectional view of an EL device of the present invention. FIG. 2 is an explanatory cross-sectional view of an EL element of a comparative example.

Example 1 First, a polyethylene terephthalate film (100 μm) was used as the plastic substrate 1.
m), an ITO film (150 nm) was wound up as a transparent anode layer 2 by sputtering to form a film (FIG. 1).
(A)).

Next, the transparent anode layer 2 was patterned by using a photolithography method and a wet etching method while winding the film to form a transparent anode layer 2 also serving as an anode extraction electrode 2a and a cathode extraction electrode 2b. (See FIG. 1A).

Next, poly [2-methoxy-5- (2'-ethyl-hexyloxy) -1,4
-Phenylenevinylene] (MEHPPV) while winding the film to obtain a 10
A 0 nm coating was formed. Next, as the cathode layer 4, Mg
Ag was vapor-deposited to a thickness of 200 nm by binary co-evaporation (see FIG. 1B).

Next, after an ITO film (150 nm) is formed on the glass substrate 5 by a sputtering method, the ITO film is formed by a photolithography method and a wet etching method.
The O film was patterned to form an anode extraction electrode 6a and a cathode extraction electrode 6b (see FIG. 1C).

Next, the glass substrate 5 and the plastic substrate 1
And were laminated. Next, the anode extraction electrode 6a formed on the glass substrate is used as the anode extraction electrode 2a of the EL element, and the cathode extraction electrode 6b formed on the glass substrate is used as the EL extraction electrode.
A conductive resin material 7 (3320D manufactured by Three Bond Co., Ltd.) composed of a modified urethane resin and silver fine particles is formed by screen printing to a thickness of 200 μm so as to be electrically connected to the cathode extraction electrode 2b of the element, respectively. The glass substrate 5 was bonded and fixed. (Figure 1
(C)).

Next, polyethylene terephthalate (20 μm), aluminum foil (2
0 μm) and an acid-modified polypropylene (30 μm) were sequentially laminated by dry lamination and extrusion lamination. Next, the EL element was covered with a moisture-resistant film in a dry nitrogen atmosphere, and the end of the moisture-resistant film was sealed by thermocompression bonding with the glass substrate 1 (see FIG. 1D). E obtained
As a result of storing the L element in a thermostat at 40 ° C. and 90% RH for 1000 hours, the light emitting area was 90% of the initial area.

Example 2 An EL element was covered and sealed with a glass substrate and a moisture-resistant film in the same process as in Example 1 except that the luminescent medium layer 3 of Example 1 was changed to a low molecular material. Examples of low molecular weight materials include copper phthalocyanine, N, N′-di (1-naphthyl) -N, N′-diphenyl-1,1′-
Biphenyl-4,4'-diamine and tris (8-quinolinolato) aluminum complex were sequentially added at 10 nm and 40 n.
It was formed by vacuum evaporation to a thickness of 50 nm with a thickness of 50 nm. As a result of storing the obtained EL element in a thermostat at 40 ° C. and 90% RH for 1000 hours, the light emitting area was 90% of the initial area.

Comparative Example 1 A polyethylene terephthalate film 1 and a moisture-resistant film 8 were thermocompression-bonded without bonding the glass substrate used in Example 1
The L element was covered and sealed (see FIG. 2). As a result of storing the obtained EL element in a thermostat at 40 ° C. and 90% RH for 1000 hours, the EL element did not emit light.

[0041]

According to the first aspect of the present invention, at least a transparent anode layer, a luminescent medium layer, and a cathode layer are sequentially laminated on one surface of a plastic substrate, and the laminate is covered and sealed with a moisture-resistant film. In the stopped electroluminescent element, since the glass substrate is laminated on the other surface of the plastic substrate, moisture from the outside is shut off, deterioration of the EL element is suppressed for a long time,
A lightweight EL element can be provided.

According to the second aspect of the present invention, power can be supplied to the EL element from an extraction electrode on a glass substrate having a higher film strength than a transparent anode layer on a plastic film. It is preferred as an embodiment of the invention.

According to the third aspect of the present invention, it is preferable as an embodiment of the first to third aspects of the present invention, since the penetration of moisture from the end of the plastic film is prevented and a sufficient adhesive strength is obtained.

According to the fourth aspect of the present invention, since the EL element of the first aspect can be manufactured at low cost, it is preferable as the embodiment of the first aspect of the invention.

[0045]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of a cross-sectional structure of an EL element of the present invention.

FIG. 2 is an explanatory diagram illustrating an example of a cross-sectional structure of an EL element of a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic base material 2 Transparent anode layer 2a Anode extraction electrode 2b Cathode extraction electrode 3 Emission medium layer 4 Cathode layer 5 Glass substrate 6a Anode extraction electrode on glass substrate 6b Cathode extraction electrode on glass substrate 7 Conductive material 8 Moisture resistant film

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K007 AB11 AB13 AB18 BB00 CA06 CB01 DA01 DB03 EA01 EB00 FA02

Claims (4)

[Claims] An electroluminescent device comprising a plastic substrate, on which at least a transparent anode layer, a luminescent medium layer, and a cathode layer are sequentially laminated, and the laminate is covered and sealed with a moisture-resistant film. An electroluminescent device, wherein a glass substrate is laminated on the other surface of a plastic substrate. 2. The method according to claim 1, wherein the glass substrate has an extraction electrode on a surface in contact with the plastic substrate, and the extraction electrode is electrically connected to the transparent anode layer and the cathode layer. 2. The electroluminescent device according to 1. 3. The electroluminescent device according to claim 1, wherein said moisture-resistant film is thermocompression-bonded to said glass substrate. 4. A step of sequentially laminating at least a transparent anode layer, a luminescent medium layer, and a cathode layer on one surface of a plastic substrate, a step of forming an extraction electrode on a glass substrate, and a step of forming a glass substrate on the other side of the plastic substrate. Laminating on the surface of
Electrically connecting the extraction electrode to the transparent anode layer and the cathode layer, and at least covering and sealing by thermocompression bonding the glass substrate and the moisture-resistant film on which the extraction electrode is formed. A method for manufacturing an electroluminescence element.