JP2000353592A - Electroluminescence element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase moisture proof and protection (from an external damage) capabilities and light emitting brightness of an EL element body. SOLUTION: An EL element comprises a rear moisture proof/protection layer, a rear electrode, a light emitting layer, a surface electrode, a surface moisture proof/protection layer, and a lead electrode. The rear moisture proof/ protection layer 11 and the surface moisture proof/protection layer 11 are formed with a blend 11 of norbornene-based cyclic polyolefin and linear hydrocarbon polymer. A silicon oxide film with a refractive index from 1.35 to 1.55 is closely interposed between an electrode surface of the surface electrode 7 and a light emitting layer surface 8. This will improve light emitting brightness more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescence device, and more particularly, to an electroluminescence device in which a main body of an electroluminescence device is shielded from the outside air (especially moisture) to protect the device against external damage and to improve emission luminance. It relates to the element.

[0002]

2. Description of the Related Art Generally, there are two types of electroluminescent devices (hereinafter referred to as EL devices), a dispersion type and a thin film type, depending on the formation contents of a light emitting layer itself. In each case, the configuration of the entire device is basically as follows. First, a back electrode and a surface electrode are arranged on both sides of the light-emitting layer, and a lead electrode for applying a voltage to both electrodes is provided to form an element substrate. Then, the element substrate is entirely sealed with a sealing material so that the element substrate is sufficiently protected from moisture except for the terminals of the lead electrodes (moisture-proof layer). The moisture-proof layer is further covered and protected (protective layer) with a protective material so as to prevent (protect) the damage and enhance the moisture-proof effect, thereby completing one EL element.

FIG. 1 is a side sectional view of a main part of the EL element of the dispersion type, which is further exemplified in the drawings.
In this figure, reference numeral 3 denotes Z doped with Mn or the like (emission center material).
A dispersion-type light emitting layer in which nS or the like is used as a phosphor powder and dispersed in a dielectric resin binder. 4 is a non-hygroscopic transparent insulating substrate such as PET (polyethylene terephthalate) 4a,
A surface electrode on which a transparent thin-film conductive layer such as ITO (indium tin oxide) 4b is laminated. The back electrode 2 is provided so as to face the front electrode 4. This back electrode 2 is made of titanium oxide,
A conductive layer 2b formed by laminating an insulating layer 2a formed by dispersing a high dielectric powder such as barium titanate in a dielectric resin binder and dispersing a conductive inorganic powder in a dielectric resin binder.
Consists of In order to apply a voltage (alternating current) to the front electrode 4 and the back electrode 2, a lead electrode 6 is drawn out from the edges of the conductive transparent thin film layer 4b and the conductive layer 2b. The EL element body composed of the above-mentioned 2, 3, 4 and 6 is provided with a surface moisture-proof / protective layer 5 on the side of the surface electrode 4 and the surface of the back electrode 2 A back moisture-proof / protective layer 1 is provided. Specifically, the two protective layers are, first of all, the surface moisture-proof / protective layer 5 and the sealing layer 5b on the surface of the transparent insulating substrate 4a with a highly moisture-proof transparent sealing material, and the entire protection (further moisture-proof and external damage). Protection from
It is composed of a double layer with the transparent protective film 5a which also serves as the transparent protective film 5a. On the other hand, the backside moisture-proof / protective layer 1 basically has
It is the same as the protective layer 5, but care is taken to obtain a greater moisture-proof effect by making the sealing layer 1b thicker or mixing a desiccant. Protective film 5
In a (1a), the terminal portion of the lead electrode 6 is externally provided and the whole is tightly sealed, but a gap is easily formed on both end surfaces. Stoppers are used.

[0004] Incidentally, the moisture-proof / protective layer is indispensable for the EL element in order to prevent deterioration of light emission luminance, and various means have been proposed accordingly. Basically, as described above, the sealing means and the protective film are used.
It depends on the moisture protection and protection of the layers. Here, firstly, as a material proposed as a sealing material, for example, a fluorine-based resin (chlorotrifluoroethylene, trifluoroethylene, etc.), a polyolefin (polyethylene, etc.), paraffin, a silicone resin, stearic acid, polystyrene, Nylon 6, 66 (in combination with zeolite, silica gel, calcium oxide, etc. in the case of nylon), PET or a compound obtained by appropriately combining these two types, epoxy resin, etc. as a raw material which is made into a film or liquid and sealed with this. (JP-A-2-192691, JP-A-60-2)
57094, etc.). There are also silicone oils. On the other hand, examples of the protective film mainly for protecting against external damage include a fluorine-based resin (chlorotrifluoroethylene flying sheet film, tubular film made of a copolymer of tetrafluoroethylene and hexafluoropropylene, butyl rubber, high density Composite films of polyethylene or polyamide and PET (disclosed in JP-A-62-51192, JP-A-5-283162, etc.) Composite films of aluminum foil with polyethylene film or PET film (JP-A-62-1399) (Disclosed in Japanese Unexamined Patent Publication (Kokai)).

[0005]

As described above, various measures have been taken to prevent moisture and protect the battery. However, at present, it is not satisfied in the following points, and further improvement is required. (1) First, the same effects are unlikely to be obtained with the above-mentioned means due to the development of EL elements that emit various colors. At the same time, there is a strong demand in the market for the development of EL devices having a longer life (maintaining luminance that can be used for a longer period of time). (2) The conventional (three in some cases) moisture-proof / protective measures by the conventional sealing material and protective film are complicated in a process and are not preferable in production. Development of means that can achieve this with a single (single) moisture-proof / protective treatment. (3) As another problem, there is emission luminance. Further improvement of the brightness has always been an issue, and various studies have been made.However, since the light emitted from the light emitting layer passes through the surface electrode and enters the eyes, a decrease in the brightness there is inevitably avoided. There is no point.

The present invention has been found as a result of intensive studies to solve the above three problems at a glance. It is achieved by taking the following measures:

[0007]

That is, the present invention provides a first aspect of the present invention.
, Which are a back moisture-proof / protective layer (1), a back electrode (2, 9), a light emitting layer (3, 8), and a surface electrode (4,
7), a surface moisture-proof / protective layer (5) and a lead electrode (6, 1).
0) wherein the back moisture-proof / protective layer and the surface moisture-proof / protective layer are formed of a blend of a norbornene-based cyclic polyolefin and a linear hydrocarbon polymer (11). An electroluminescent device characterized by the above.

[0008] Claim 2 is provided as a means for further improving the emission luminance. That is, in the first aspect of the present invention, a silicon oxide film having a refractive index of 1.35 to 1.5 is closely interposed between the electrode surface of the surface electrode (4, 7) and the light emitting layer (3, 8). Things.

[0009] Claims 3 and 4 are also provided as preferred means dependent on the claims 1 and 2. Hereinafter, the present invention will be described in detail with the following embodiments.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the structure of an EL element which is the basis of the present invention (back moisture-proof / protective layer 1, back electrode 2, light-emitting layer 3, surface electrode 4, surface moisture-proof / protective layer 5, and lead electrode 6). Is
This is as illustrated in FIG.

The phosphor powder as a base material for forming the light emitting layer 3 is
Mainly, ZnS is used as a base to emit green, blue and red colors. The difference in the colors depends on what is doped into ZnS as a light emitting center material. Of course, there is no particular limitation on the type of the base. In the case of the dispersion type, the dielectric resin binder for dispersing the phosphor powder can be exemplified by an elastomer resin such as a polyester elastomer or a fluorine-based elastomer, and a cyanated polymer such as cyanoethyl polyvinyl alcohol and cyanoethyl cellulose. And titanium oxide, barium titanate, PZT (PbO.Zr
In some cases, a highly dielectric inorganic powder such as an O.TiO ₂ mixed sintered body is mixed.

Since the back electrode 2 does not need to be particularly transparent, for example, a conductive paste obtained by mixing a conductive powder of conductive carbon black, silver, copper or the like with an acrylic resin is coated with an insulating layer (PET). Or an insulating layer made of the above-mentioned elastomer resin or another insulating material), or laminated on the back surface 2a or by laminating another conductive material such as aluminum foil instead of the conductive paste. . Again, there are no special restrictions on the type.

The surface electrode 4 needs to have higher transparency so as not to lower the luminance of light emitted from the light emitting layer 3 as much as possible. For that purpose, first, the transparency of the base material itself is required. The base material (electrical insulation) is, for example, a resin-based biaxially stretched PET or polyethylene naphthalate film, polyarylate, polyether.
Amorphous films such as tersulfone and cyclic polyolefin are preferable because they are excellent in heat resistance, strength and the like. A glass plate is represented by an inorganic material. Here, in terms of transparency, a glass plate is most excellent, and next is a cyclic polyolefin. Considering ease of use, overall, the PE
T or cyclic polyolefin film. The base material is provided with a conductive layer serving as an electrode, and the conductive layer needs to be as transparent as possible. Although there are various types of conductive layers, it is preferable that the above-mentioned ITO be used as a conductive material and be deposited and deposited in a thin film form by a PVD method, mainly a sputtering method.

It is needless to say that the thickness of the entire surface electrode 4 is preferably as thin as possible from the viewpoint of transparency. For this purpose, the thickness of the substrate and the thickness of the conductive layer may be reduced. Specifically, first, the substrate is about 100 to 200 μm in consideration of ease of handling (strength).
The conductive layer also needs to have a predetermined electric resistance value (about 10 ⁻² Ω / port or less), film strength, and the like. . Note that the transparency based on the conductive layer has a height difference due to an interference action with the film thickness. Therefore, it is preferable to select and set the film thickness to be increased. It is roughly 150nm, 3
00 nm, 450 nm, 600 nm, 750 nm, 90
0 nm, and appears in a waveform state that it becomes lower at an intermediate film thickness.

Next, the back moisture-proof / protective layer and the surface moisture-proof / protective layer which are main parts of the present invention will be described. As described above, in general, means for preventing and protecting the EL element main body include:
The back side and the front side differ in the contents of the means (material used, assembling method, etc.), and have a complicated configuration. In the present invention, the sealing for moisture prevention is performed at once by coating both sides of the EL element body, and both sides with a kind of a blend of a norbornene-based cyclic polyolefin and a linear hydrocarbon polymer. Thus, an EL element capable of protecting against external damage accompanied by further moisture proofing is obtained. Therefore, the subject of the present invention cannot be achieved by simply using only the cyclic polyolefin, only the linear hydrocarbon polymer, or even a blend of the above materials and the like with the conventional materials described above.

Therefore, one of the norbornene-based cyclic polyolefins (hereinafter referred to as NPO) of the blend will be described. NPO is an amorphous polymer having an alicyclic group based on norbornene in the main chain obtained by polymerizing norbornene or a derivative thereof as a main monomer, and a crystalline acyclic polymer such as polypropylene or polyethylene. Poly α
-Different from olefins, it has various features (low refractive index of 1.53, high hardness, etc.). The polymers belonging to the NPO can be roughly classified into (1) a single polymer obtained by polymerization (ring opening and hydrogenation) of only a norbornene or a derivative thereof.
(2) A copolymer obtained by copolymerizing a norbornene or a derivative thereof with an acyclic α-olefin (ethylene, propylene, etc.). (3) A modified polymer obtained by grafting a vinyl monomer such as maleic acid onto the polymer of (1) or (2). (4) 4 of various blended polymers blended between the above-mentioned polymers (1) to (3) or with other polymers.
One is. Among these, (1) or (2) is preferable, and (2) is more preferable. This is because they are excellent in high moisture barrier properties, protection against external damage (impact resistance), adhesion, workability (as a moisture-proof / protective layer), and the like.

Here, the norbornene or its derivative (monomer) constituting the main component of the NPO will be exemplified as follows. First, norbornene (bicyclo [2.2.
1] -2-heptene) and, tetracyclo indicated by the formula 2 [4.4.0.1 ^2.5. 1 ^7.10 ] -3-dodecene.

(Formula 1)

(Formula 2)

The derivatives of formula 1 are mainly
And / or a non-polar group of a C _1-4 alkyl group at the 9-carbon position. Substituted compounds in which a polar group such as a halogen group such as a chlorine atom, an aliphatic carboxylic acid ester group, or an alkoxycarbonyl group is substituted at any of the positions can be given.
Derivatives of formula 2 are mainly non-polar C _1-4 alkyl groups at positions 5 and / or 6. A halogen group such as a chlorine atom at any of the positions, methyl of an aliphatic carboxylic acid,
Examples include substituted compounds in which a polar group such as an ester group such as ethyl or an alkoxy (methoxy, ethoxy, etc.) carbonyl group is substituted. Among these derivatives, the polar group-substituted product is more effective in improving the adhesion than the non-polar group-substituted product, but is slightly inferior in terms of the moisture barrier. Therefore, an appropriate blend of both is considered as an effective example. The details thereof are described in detail in Japanese Patent Application Laid-Open No.
No. 8284.

As the α-olefin in the copolymerization with the norbornene-based cyclic olefin, ethylene, propylene, butene-1 or a monomer mixture thereof is preferably exemplified. The copolymerization ratio maintains the properties of the polymer based on the norbornene-based cyclic olefin (mainly, hardness, moisture barrier, transparency, adhesion, etc. as a protective function against trauma), and a higher protective function (appropriate elasticity). Force), to provide processability and the like, the amount of the norbornene-based cyclic olefin monomer is 10 to 80 mol%, preferably 20 to 55 mol%.

The molecular weight of the NPO is preferably selected in consideration of appropriate strength, hardness, blendability with a linear hydrocarbon polymer described later, workability, and the like. Therefore, it is not preferable to be small or large. From this, a reasonable range is preferably about 5 to 35 in terms of MFR. Further, when this is measured by Tg, it is about 100 to 150 ° C. The degree of non-crystallization is about 70 to 100%.

Next, the linear hydrocarbon polymer to be blended will be described. First, the polymer is particularly selected,
The compatibility with the norbornene-based cyclic polyolefin is extremely good, and thus a uniform composition can be obtained. This one composition has an extremely high moisture barrier (moisture proof effect) and protection from external damage, and also has good coating processability, so that an EL element having excellent moisture proofing and protection can be obtained with this further coating. Depends on The reason why the extremely high moisture barrier is exhibited here is that the formed moisture-proof / protective layer is in close contact with the light-emitting layer, the front and back electrodes, and has extremely high density, and is liable to be accompanied by bubbles. This is considered to be due to the penetration into the bubble portion of the layer and complete sealing.

The linear hydrocarbon polymer exhibiting the above-mentioned effects and effects is, specifically, a saturated or unsaturated polymer having a molecular weight of about 300 to 10,000. Among these, a saturated molecular weight of about 40 to 1000 (melting point of about 40 to 105)
° C) or a polyethylene wax having an intermediate molecular weight (about 3000 to 6000) between the paraffin and polyethylene. More preferably _C 24 _{-C 70} paraffin wax (molecular weight 38 to 882) (mp 51-105
° C). The polymer may be mixed with some branched polymers.

The blend ratio of the norbornene-based cyclic polyolefin and the linear hydrocarbon polymer depends on the type of the polyolefin (whether homopolymer or copolymer, molecular weight, type of component) with respect to the formation of the desired moisture-proof / protective layer. Etc.) and the type of the polymer to be blended therewith (particularly, molecular weight-melting point) is determined naturally by how to select the combination. Considering such a situation, the ratio is specifically exemplified by the former 30 to 80 parts by weight, preferably 40 to 70 parts by weight, and the latter 70 to 20 parts by weight, preferably 60 to 70 parts by weight.
-30 parts by weight. Incidentally, among such composition ratios, it is better to slightly increase the number of linear hydrocarbon polymers. This is because when the amount of the linear hydrocarbon polymer is large, a denser film is formed, and the effect in terms of moisture prevention tends to be increased.

Next, means for forming the moisture-proof / protective layers (1) and (2) on the front and back will be exemplified. This is roughly divided into the following (a) ~
(C). (A) A seamless tubular film (having a thickness of about 30 to 100 μm) of the above-mentioned blend is molded in an EL element body, heat-shrinked, and first, both surfaces are brought into close contact with each other. Next, both sides are melted and sealed. At this time, it is preferable to apply an organic solvent (described later) to the inside of the portion of the film to be sealed in advance, and to melt the surface layer extremely before melting. This is because it acts as if the same adhesive is applied to the seal portion, and is easily and completely sealed without wrinkles or the like. The organic solvent is preferably a slightly poorer solvent than a very good solvent. The use of this solvent is not limited to the case of both-side fusing seal, and the method of using the solvent in the same manner in the case of both-side adhesion is adopted. -It is more preferable because protection is provided.

(B) First, the blend is dissolved in an organic solvent, for example, an aromatic hydrocarbon such as xylene, an aliphatic halogenated hydrocarbon such as tricrene, or a cyclic ether such as tetrahydrofuran. The amount of the solvent to be used may be appropriately determined in view of the coating and the ease of removing the solvent by evaporation after coating. The obtained solution is coated on both sides of the EL body by a coating means such as a roll coater or screen printing. At this time, it is preferable that the solution also wraps around the side surface and is coated. After coating, hot air drying is performed to remove the contained solvent. It is preferable that this coating and hot air drying be repeated several times rather than once. This is because the desired moisture-proof / protective layers can be more easily adhered to the EL element body surface with more complete adhesion (without entrapment of bubbles and the like) and more uniform smooth surface. Because it is obtained. The thickness of the layer may be smaller than that of the film (the thickness is about 30 to 100 μm).

(C) fusing the blend and melting
The so-called hot-met method is used for directly coating the L element body. Of the above three forming means, either (b) or (c) is preferably used.

By performing as described above, the entire EL element main body including the connection origin of the lead electrode (6) drawn out from the side surface is completely sealed, and a high degree of moisture proofing and protection from external damage are at once. An EL element having a function can be obtained. As a result, the life of the EL element is much longer than that of the EL element protected and protected by the conventional means, and the quality performance is further improved. Therefore, it is not necessary to further laminate another protective layer on both the moisture-proof / protective layers, but this is not to be excluded. In this regard, there is a danger that the connection portion of the lead electrode (6) may have insufficient sealing and adhesion, and that the adhesion with the moisture-proof / protective layer may peel off during operation. In order to prevent danger, the part is, for example, acrylic,
It is preferable to further overcoat with a urethane-based adhesive resin.

The obtained EL element is different from the conventional one in which moisture protection and protection against trauma are performed by a multi-layer coating of different materials, and has high transparency (small refraction and no birefringence). (1) Since it is composed of one composition material and one layer of coating, the emission luminance is also improved as compared with the conventional method.

However, in order to achieve a further improvement, the present invention finds the above-mentioned claim 2 and also features this. The means will be described. This is because silicon oxide having a refractive index of 1.35 to 1.5, preferably 1.4 to 1.48 is added between the surface of the light emitting layer 3 and the electrode surface of the surface electrode 2.
This is achieved by tightly interposing a thin film. Here, the silicon oxide film having the above-mentioned refractive index is used not only because it has excellent light transmittance than other metal oxide films, but also when it is used in combination with an electrode film such as an ITO film to further increase the transmittance. This is because the adhesion to the electrode film surface is good.

The means for interposing the silicon oxide film in close contact may be, for example, a generally known sol-gel method, CVD method, PV method, or the like.
D method and the like can be used. However, it is needless to say that the silicon oxide film is preferably a 100% silicon oxide film having the highest possible purity. In terms of this high-purity silicon oxide film, the above-described methods are not sufficient, and are likely to be mixed films of silicon oxides having slightly different refractive indexes. In particular, the following method can be recommended as a method of forming pure silicon dioxide having a constant refractive index, having high adhesion, and easily forming a film.

It is a perhydrohydrosilazane (hereinafter HP)
(Abbreviated as S) is coated on the electrode surface of the surface electrode 2 and then changed to a silicon dioxide film by a chemical treatment. Here, first, the HPS is an organic solvent-soluble inorganic polymer having-(SiH2NH)-as a basic unit.
It is an oligomer having a relatively low molecular weight (number average) of about 500 to 2500. Organic solvents include aromatic hydrocarbons such as xylene, aliphatic ethers such as dibutyl ether, and alicyclic hydrocarbons such as cyclohexene.

In order to convert the HPS into a silicon dioxide film, basically, an organic solvent solution of PHS is first applied to the electrode surface of the front electrode 2 by an appropriate method, and then 400 ppm in the presence of moisture and oxygen. This can be achieved by firing at about ° C. However, firing at this temperature is not particularly problematic when the base material of the surface electrode is a glass plate, but when it is made of the resin, lower temperature firing is required. The following cases can be exemplified as a method of forming a silicon oxide film by low-temperature baking (for example, 150 ° C. or lower). (1) First, PHS is made of, for example, polysilazane with silicon alkoxide (for example, disclosed in JP-A-5-238827) and polysilazane with glycidol (for example, JP-A-6-238).
-122852) or metal (pd, pt
Etc.) Carboxylate-added polysilazane (for example,
299118). (2) Then, an organic solvent solution of any of the adducts is
After coating on the electrode surface, the electrode surface is subjected to a low-temperature heat treatment (around 130 ° C.) in a steam atmosphere, or is first brought into contact with steam containing an aliphatic amine (catalyst) at room temperature, and then further heated to a higher temperature ( Around 90 ° C) high humidity (around 80% RH)
Leave below.

With respect to the thickness of the silicon oxide, the film thickness is set so that the transparency becomes the highest as well as the film strength, and as a result, the light emission luminance increases.
In the range of 1000 nm. However, looking at only the transparency here, it does not mean that simply thinning is sufficient. This is a peculiar optical phenomenon observed in the case of a multilayer stack of two or more layers. Actually, for example, the transparent conductive layer film 1 showing the maximum transparency exemplified in the above-mentioned 0009
Even if the film is first formed on a substrate with a thickness of 50 nm, and a silicon oxide film is laminated thereon, for example, 70 to 80 nm, the transparency is not improved. In this case, the conductive layer film is
A further improvement is seen at 80 nm (in which one layer shows the lowest light transmission). These relationships will ultimately set the film thickness by a detailed experiment, but as a prerequisite, the film thickness of each layer is calculated in advance using the basic formula regarding the Maxwell electromagnetic field in the optical design. It is more effective to put

[0036]

Next, the present invention will be described in more detail with reference to examples together with comparative examples. For the moisture resistance, the obtained EL element was kept at 60 °
Place in a 95% C-RH atmosphere and apply 80V to the lead electrode.
While applying a voltage of -400 Hz (DC power supply),
Light emission was continued for a while, and the change with time in the light emission luminance was measured and compared. Here, the brightness is “B” manufactured by TOPCON.
M-7 type "and FL (foot Lambert). Impact resistance (strength against trauma) was measured indirectly by measuring pencil hardness. That is, the pencil hardness number was large. When the hardness is high, the film tends to be broken, and the evaluation is such that the film tends to be weak against impact.

(Example 1) First, seven EL element bodies were manufactured by the following method. Transparent PET film having a thickness of 188 μm and 80 × 150 mm (refractive index: 1.64, total light transmittance: 8)
(7.5%) Sputter ITO on one side of 7a (DC
The surface electrode 7 was obtained by providing a 150 nm-thick ITO transparent conductive film 7b by magnetron method. Its total light transmittance was 88%.

On the other hand, a zinc sulfide-based fluorescent powder having an average particle diameter of 27 μm (Mg was used as a light-emission center and was doped).
70 parts by weight of the above and 30 parts by weight of a polyester elastomer were sufficiently mixed and dispersed with 3-methoxybutyl acetate (a solvent for the elastomer) to prepare a paste for a light emitting layer. Then, the paper is applied to the surface of the ITO conductive film of the surface electrode 7.
The strike was applied with an applicator and dried with hot air at 120 ° C. for 20 minutes to form a light emitting layer 8 having a thickness of 35 μm. In this light emitting layer, bubbles were slightly entrapped. Next, the light emitting layer 8
The back electrode 9 was laminated on the surface as follows. First 3
-An insulating layer liquid obtained by adding and mixing barium titanate (containing 60% of the total solid content) to a fluorine-based elastomer dissolved in ethoxybutyl acetate was applied to the surface of the light emitting layer 8 at 120 ° C-dry with hot air for 20 minutes, thickness 100μm
An insulating layer 9a was provided. Then, a conductive paste (an ultraviolet curable acrylic low molecular weight compound is added to the conductive paste) on the insulating layer surface.
Bones were mixed) and cured with ultraviolet light to a thickness of 35μ.
m of carbon conductive layers 9b were laminated. Finally, the ITO
A lead wire was connected to the center of the transparent conductive film 7b and the carbon conductive layer 9b, and the lead electrode 10 was drawn out.

Next, using one of the EL element bodies, a moisture-proof / protective layer was provided on the entire surface by the following method. First, a random copolymer of norbornene and ethylene (Tg13
0 to 135 ° C., MFR 12 to 13) 40 parts by weight of powder and 60 parts by weight of paraffin wax (mp 82 to 83 ° C.) are dissolved in xylene (solid concentration 28% by weight) to prevent moisture.
A liquid for a protective layer was prepared. Here, the MFR (melt flow rate) means a flow rate (g / 10 min) at 260 ° C. according to ASTM D1238. Using the liquid for the moisture-proof / protective layer, the front and rear electrode surfaces and the entire peripheral side surface of the EL element body are first entirely coated by screen printing and then dried with hot air to form a single layer. 15-17
The desired EL element was obtained by providing a moisture-proof / protective layer 11 of μm. In order to confirm the moisture-proof / protective effect, the effect of the moisture-proof property on the emission luminance (hereinafter simply referred to as moisture-proof property) and the impact resistance were tested. The results are summarized in the graph of FIG. The impact resistance was a pencil hardness of 3 to 4B. The structure of the obtained EL element was shown in the side sectional view of FIG.

Example 2 Using one of the EL element bodies obtained in Example 1, a moisture-proof / protective layer was provided on the entire surface by the following method. The same procedure as in Example 1 was repeated except that a paraffin wax was replaced by a polyethylene wax having a molecular weight of 3600, and the mixing ratio was 55% by weight. Example 1
The entire surface of the EL element body is coated by screen printing in the same manner as described above, and dried with hot air to form a single layer having a thickness of 15 to 1 mm.
A 7 μm moisture-proof protective layer was provided. The EL element thus obtained was similarly tested for moisture resistance and impact resistance in order to confirm the moisture proof and protective effects. The results are summarized in Table 1 for the moisture resistance, and the impact resistance was 3 to 4B.

(Comparative Example 1) Using one of the EL device bodies obtained in Example 1, a moisture-proof / protective layer was provided on the entire surface thereof as follows. First, paraffin wax having a melting point of 104 ° C. was dissolved in hexane (solid content: 28% by weight) to prepare a moisture-proof protective solution. Next, using this solution, the entire surface of the EL element body was coated by screen printing in the same manner as in Example 1, and dried with hot air to provide a moisture-proof / protective layer having a thickness of 15 to 17 μm. Was. However, in this case, hot air drying is 7
1 ° C. for 20 minutes. The obtained EL element was similarly tested for moisture resistance and impact resistance in order to confirm the moisture proof and protective effects. The results are summarized in the graph of FIG. The impact resistance was 6-7B. When the EL element after the test was bent to about 60 degrees, cracks started to enter the protective layer and peeled off when the element was further bent to about 70 degrees.
However, in Examples 1 and 2, this phenomenon did not occur and they were firmly adhered.

Comparative Example 2 One of the EL element bodies obtained in Example 1 was used, and a single layer of a moisture-proof / protective layer was provided on the entire surface thereof as follows. First, a random copolymer of norbornene and ethylene used in Example 1 (Tg1
30-135 ° C, MFR 12-13) The powder was dissolved in xylene (solid content concentration 28% by weight) to prepare a liquid for a moisture-proof / protective layer. Next, using this solution, the entire surface of the EL element body is coated by screen printing in the same manner as in Example 1, and then dried with hot air to a thickness of 15 to 17 μm.
Was provided with a moisture-proof / protective layer. The obtained EL element was similarly tested for moisture resistance and impact resistance in order to confirm the moisture proof and protective effects. The results are summarized in Table 1 for moisture resistance.
The impact resistance was 1-2B. When the EL element after the test was bent to about 70 degrees, fine cracks were formed in the protective layer, but no peeling was observed.

(Example 3) EL element body obtained in Example 1
Moisture proof and protection over the entire surface using one of the following
Layers were provided. 8-methyl-8-carboxymethyltetra
Cyclo [4.4.0.1^2,5. 1 ^7,10] -3-do
Ring-opening polymerization of decene (derivative) and hydrogenation
Viscosity 0.61 dl / g (30 ° C in chloroform, concentrated
0.5 g / dl) and a melting point of 66 °
50 parts by weight of paraffin wax C to chloroform
Dissolve (solid content concentration 30% by weight) and prepare liquid for moisture-proof / protective layer
Made. Then, using this liquid, a screen was formed in the same manner as in Example 1.
The entire EL element body is coated by hot printing and dried with hot air.
And a 25 μm thick moisture-proof / protective layer
Was. Similarly, the obtained EL element has the moisture-proof / protective effect.
The moisture resistance and impact resistance were tested to confirm. Result is
The moisture resistance is summarized in the graph of FIG.
Ｂ4B. After the test, fold the EL element to about 70 degrees.
The protective layer peeled without cracking.
Did not.

Example 4 (corresponding to claim 2) First, ITO was sputtered on the same PET film as in Example 1 to form a 73 nm-thick transparent conductive layer (refractive index: 1.9).
5) was provided, and a silicon oxide film was further laminated on the conductive layer surface by the following method. PH which can be fired at low temperature as exemplified above
After coating a xylene solution (solid content concentration 8% by weight) of an S adduct (N-V110 type, manufactured by Tonen Co., Ltd.), the solvent was first removed by evaporation, and then this was added to a gaseous atmosphere of a triethylamine aqueous solution. The contact was made at 25 ° C. for 5 minutes. And further, steam (90-95 ° C, 80-90 ° C)
% RH) and decomposition into silicon oxide and film formation were completed indirectly for 5 minutes. The thickness of the laminated film was 74 nm. When the film was subjected to IR spectrum analysis, very little Si
It was confirmed that there was an absorption peak derived from -N, but the other was only absorption peaks derived from Si-O (1100 and 500 cm ^-1 ). It was also confirmed that it was colorless and transparent (it could be said that it was almost 100% silicon dioxide). This is called a surface electrode S. The total light transmittance of the electrode S is 94%, which means that the electrode S is improved about 1.06 times as compared with the first embodiment.

Using the surface electrode S obtained above, a light emitting layer 8 and a back electrode 9 were sequentially laminated on this under the same conditions as in Example 1 to produce an EL element body for connecting the lead electrode 10. Finally, a single layer of moisture-proof / protective layer comprising norbornene and parahin wax was coated on the entire surface of the EL element body under the same conditions as in Example 1 to obtain a desired EL element. The light emission luminance of this was 20.

With respect to the obtained EL device, a change with time in light emission luminance was measured in the same manner as in Example 1, and is shown in a graph of FIG. As is clear from the graph, there is almost no difference in the change over time of the light emission luminance as compared with the above example, but it can be seen that the luminance is increased about 1.15 times.

[0047]

As described above, the present invention has the following advantages.

Regarding the moisture-proofing / protecting means of the EL element body, it is possible to protect the moisture-proofing / protection by covering the EL element body with a single layer of one material having excellent transparency without using a complicated multilayer structure with various materials. It has become possible to obtain an EL device having more improved light emission luminance and protection (protection from external force) than conventional emission luminance.

By interposing a specific transparent silicon oxide layer between the surface electrode and the light emitting layer in close contact, an EL device having a higher level of light emission luminance can be obtained.

It is easier to control the production of EL elements than ever before, the yield is further improved, and the production speed is dramatically increased.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a main part of a general EL element.

FIG. 2 is a side sectional view of the EL element of Example 1.

FIG. 3 is a graph showing a relationship of luminance with time in each example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 5 Moisture-proof / protective layer consisting of moisture-proof layer and protective film 2-4 EL element body 7a PET film 7b ITO conductive film layer 8 ZnS-based light emitting layer 9a Fluorine-based elastomer insulating layer 9b Carbon conductive layer 11 Example 1) Moisture-proof / protective layer

Claims (4)

[Claims] 1. A back moisture-proof / protective layer (1), a back electrode (2,
9) an electroluminescent element comprising a light-emitting layer (3, 8), a surface electrode (4, 7), a surface moisture-proof / protective layer (5), and a lead electrode (6, 10); An electroluminescent device, wherein the protective layer and the surface moisture-proof / protective layer are formed by a blend (11) of a norbornene-based cyclic polyolefin and a linear hydrocarbon polymer. 2. The method according to claim 1, wherein the surface electrodes (4,
The refractive index between the electrode surface of 7) and the light emitting layer (3, 8) surface was 1.
An electroluminescent device comprising a silicon oxide film having a thickness of 35 to 1.5 in close contact therewith. 3. The method according to claim 1, wherein the norbornene-based cyclic polyolefin is either a homopolymer of a norbornene-based derivative or a copolymer of a norbornene-based or derivative thereof and an α-olefin. The electroluminescent device according to the above. 4. The linear hydrocarbon polymer having a melting point of 30 to 1
The electroluminescent element according to any one of claims 1 to 3, which is a paraffin wax to an ethylene wax at 10 ° C.