JPH10335064A - Electroluminescent element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroluminescent element in which the filling ratio of light emitting grains in a light emitting layer can be easily enhanced, and in which brightness of light emission is drastically improved. SOLUTION: An electroluminescent element is composed of a transparent base material 1, a transparent conductive layer 2 arranged on the back surface of the transparent base material 1, a light emitting layer 8 containing light emitting grains 8 and matrix resin and arranged on the back surface of the transparent conductive layer 2, and a back surface electrode 6 arranged on the back surface of the light emitting layer 8, the light emitting layer 8 is formed by containing matrix resin and composed of a transparent supporting layer 3 arranged on the transparent conductive layer 2 side, an insulating layer 5 containing insulating materials and arranged on the back surface electrode 6 side, and a light emitting grain layer 4 substantially formed of grains embedded between the supporting layer 3 and the insulating layer 5 and in which the grains contains light emitting grains 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescence device (hereinafter, referred to as an "EL device") having a light-emitting layer containing light-emitting particles and a matrix resin, and more particularly to a conventional "dispersed light-emitting layer". And a high-brightness light-emitting EL element based on an idea different from the above.

[0002]

2. Description of the Related Art An EL element having a so-called "dispersed light-emitting layer" formed by dispersing phosphor particles such as a phosphor in a matrix resin such as a high dielectric constant polymer is known from the following documents. ing. For example, Japanese Patent Publication No. 59-148
No. 78 discloses a transparent substrate, a transparent electrode layer, an insulating layer composed of only a vinylidene fluoride-based matrix resin, a light-emitting layer composed of a vinylidene fluoride-based matrix resin and phosphor particles, the same insulating layer as described above, and An EL element in which back electrodes are stacked in this order is disclosed. JP-B-62-59879 discloses a polyester film, an ITO electrode, a light-emitting layer composed of cyanoethylated ethylene-vinyl alcohol copolymer (matrix resin) and phosphor particles, and an aluminum foil (back electrode). An EL element formed by laminating in this order is disclosed.

[0003]

However, in such a "dispersed light emitting layer", it was difficult to increase the light emission luminance. The reason is that in the light-emitting layer forming coating material in which the light-emitting particles are dispersed in a matrix resin solution, the light-emitting particles having a higher specific gravity than the matrix resin are liable to settle. This is because it is difficult to make the phosphor particles uniformly dispersed in the matrix resin. In addition, when the amount of the luminescent particles in the coating material is increased in order to increase the filling rate of the luminescent particles in the luminescent layer, the dispersibility is reduced. Furthermore, since it is relatively difficult to increase the thickness of the light-emitting layer with a uniform thickness using such a dispersion-type paint, the number of coatings must be increased to increase the thickness of the light-emitting layer in order to increase the luminance. Therefore, productivity was poor, and it was difficult to produce a large-area sheet-like EL element.

[0004] Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art by easily increasing the filling rate of luminescent particles in the luminescent layer and thereby dramatically improving the luminous brightness.
It is to provide an element. Another object of the present invention is to provide a method of manufacturing an EL element capable of manufacturing a large-area sheet-shaped EL element having high emission luminance with high productivity without using the above-mentioned dispersion paint. It is in.

[0005]

According to one aspect of the invention, a) a transparent substrate (1), b) a transparent conductive layer (2) disposed on the back of the transparent substrate (1), c. A) a light-emitting layer (8) including a phosphor particle (7) and a matrix resin, and disposed on the back of the transparent conductive layer (2); and d) a back electrode (6) disposed on the back of the light-emitting layer (8). ), The light-emitting layer (8) has (c-
1) A transparent conductive layer comprising a matrix resin (2)
A transparent support layer (3) disposed on the side of the back electrode (6), comprising an insulating material (c-2) disposed on the side of the back electrode (6); An electroluminescent device is provided, comprising a luminescent particle layer (4) comprising luminescent particles (7) embedded in both the layer (3) and the insulating layer (5).

According to another aspect of the present invention, a transparent substrate (1), a transparent conductive layer (2) disposed on the back surface of the transparent substrate (1), luminescent particles (7) and a matrix resin A light emitting layer (8) disposed on the back of the transparent conductive layer (2),
And a back electrode (6) disposed on the back of the light emitting layer (8)
And i) preparing a transparent substrate (1) having a transparent conductive layer (2) laminated on one surface, and ii) forming a transparent substrate on the transparent conductive layer (2). A coating material for forming a support layer (3) containing a matrix resin is applied, and before the coating material is solidified, particles containing the phosphor particles (7) are dispersed in a layer, and the particles are partially dispersed in the coating material. After that, the paint is solidified to form a transparent support layer (3) and a luminescent particle layer (4) adhered to the support layer (3). Iii) On the luminescent particle layer (4) A coating material for forming an insulating layer (5) containing an insulating substance is applied to the coating layer, and the coating material is solidified to form an insulating layer (5) in close contact with the luminescent particle layer (4); iv) an insulating layer Laminating the back electrode layer (6) on (5);
A manufacturing method comprising the steps is provided.

In the EL device of the present invention, the luminescent particle layer (4) contained in the luminescent layer (8) is substantially composed of particles containing the luminescent particles (7), and the support layer (3) and the insulating layer ( 5), and is in close contact with both the support layer (3) and the insulating layer (5), so that the filling rate of the luminescent particles in the luminescent layer (8) can be easily increased, and Light emission brightness is dramatically improved. In addition, by manufacturing the EL element by the manufacturing method of the present invention including the above steps i) to iv), it is not necessary to use a coating material in which luminescent particles are dispersed as in the related art, and a large area with high luminous brightness is obtained. Can be manufactured with high productivity.

[0008]

The cross-section of an EL device according to one embodiment of the DETAILED DESCRIPTION OF THE INVENTION The EL device present invention shown in FIG. This EL element is a sheet-like EL element comprising a laminate comprising a transparent substrate (1) and a transparent conductive layer (2), and a light emitting layer (8) sandwiched between a back electrode (6). It is. This embodiment is substantially the same as a conventional dispersion-type EL element except for the structure of the light-emitting layer (8). The light-emitting layer (8) (to be described in detail later) includes a transparent support layer (3) containing a matrix resin, an insulating layer (5) containing an insulating substance, and a light-emitting layer sandwiched therebetween. It has a structure in which a luminescent particle layer (4) substantially consisting of body particles is laminated so as to be in close contact with each other. The thickness of the entire EL element is usually 5
The range is from 0 to 3000 μm.

Transparent Substrate The transparent substrate may be the same as the substrate used for the dispersion type EL element, and for example, glass, plastic film, etc. can be used. An example of such a plastic film is, for example, polyethylene terephthalate (PE
T), polyester resins such as polyethylene naphthalate (PEN); acrylic resins such as polymethyl methacrylate and modified polymethyl methacrylate; fluorine resins such as polyvinylidene fluoride and acrylic-modified polyvinylidene fluoride; polycarbonate resins; It is a film such as a vinyl chloride resin.

The transparent substrate may be a single-layer film as shown in FIG. 1, but may be a multilayer film. For example, at least one of the multilayer films has high transparency,
In addition, by including a dye that develops a color complementary to the emission color of the light emitting layer, the whiteness of light can be increased. As such a dye, when the emission color of the light emitting layer is blue-green, a red or pink fluorescent dye such as rhodamine 6G, rhodamine B, or a perylene dye is preferable. A processed pigment formed by dispersing these dyes in a resin can also be used. In addition, the front and back surfaces of the transparent substrate are usually flat, but the surface not in contact with the transparent conductive layer may have regular irregularities as long as the effects of the present invention are not impaired.

The light transmittance of the transparent substrate is usually 60% or more,
It is preferably at least 70%, particularly preferably at least 80%.
The “light transmittance” in this specification is an ultraviolet / visible spectrophotometer “Model number: U best V-560” manufactured by JASCO Corporation.
Means the light transmittance measured using 550 nm light. The thickness of the transparent substrate is usually 10 to 1000 μm when forming a sheet-like EL element. Further, as long as the effects of the present invention are not impaired, additives such as an ultraviolet absorber, a moisture absorbent, a coloring agent, a fluorescent substance, and a phosphorescent substance may be contained in the transparent substrate.

Transparent conductive layer The transparent conductive layer is disposed on the rear surface of the transparent substrate so as to be in close contact with it. As the transparent conductive layer, a transparent electrode such as an ITO (indium tin oxide) film used for a dispersion type EL element can be used. The thickness of the transparent conductive layer is usually 0.1.
01 to 1000 μm, and the surface resistance is usually 500
Ω / □ or less, preferably 1 to 300 Ω / □. Also,
The light transmittance is usually 70% or more, preferably 80% or more.

The ITO film is formed by a film forming means such as ordinary vapor deposition, sputtering, and application of a paste. FIG.
In the embodiment shown in (1), it is provided directly on the transparent substrate, but after providing a primer layer on the transparent substrate, an ITO film may be formed on the primer layer. Further, instead of the primer layer, the surface of the transparent substrate may be subjected to an easy adhesion treatment such as a corona treatment or a silicon oxide coating. Alternatively, after providing an ITO film on the light emitting layer,
A transparent substrate can be laminated on the film.

Back Electrode Layer The back electrode layer is disposed on the back side of the light emitting layer, that is, on the insulating layer side of the light emitting layer. In the embodiment shown in FIG. 1, they are arranged so as to be in direct contact with the light emitting layer. In addition, a resin layer may be provided between the light emitting layer and the light emitting layer for the purpose of increasing the adhesive strength to the back electrode. As the resin of this resin layer, for example, a high dielectric constant polymer described later is used. Further, the resin layer may contain inorganic inorganic particles.

The back electrode is made of a metal film such as aluminum, gold, silver, copper, nickel, chromium or the like used for the dispersion type EL device; a transparent conductive film such as an ITO film; or a conductive film such as a conductive carbon film. Can be used. The metal film is, for example, a deposition film, a sputtered film, a metal foil, or the like. The thickness of the back electrode is usually 5 nm to 1000 μm. When the back electrode is also made of a transparent conductive film and the insulating layer is transparent, it is possible to emit light on both the front and back surfaces of the EL element.

Support Layer The support layer of the light-emitting layer is preferably disposed so as to be in close contact with the back surface of the transparent conductive layer. Thereby, the luminous efficiency of the light emitting layer can be easily increased. The support layer is a transparent layer containing a matrix resin. The thickness of the support layer is usually 3 to 1000
μm, and the light transmittance is usually 70% or more, preferably 80% or more.
% Or more. The matrix resin may be an epoxy resin, a high dielectric constant polymer, or the like used for the light emitting layer of the dispersion type EL element. The high dielectric constant polymer is a polymer having a dielectric constant of usually about 5 or more, preferably 7 to 25, particularly preferably 8 to 18 measured by applying an alternating voltage of 1 kHz. If the dielectric constant is too low, the light emission luminance may not be increased, while if it is too high, the life of the light emitting layer may be shortened.

Examples of the high dielectric constant polymer include vinylidene fluoride resin, cyano resin and the like. The vinylidene fluoride resin is obtained, for example, by copolymerizing a mixture of a vinylidene fluoride monomer and at least one other fluorine monomer. Examples of other fluorine-based monomers include ethylene tetrafluoride, ethylene trifluoride chloride, and propylene hexafluoride. Examples of the cyano-based resin include cyanoethyl cellulose, cyanoethylated ethylene-vinyl alcohol copolymer, and the like.

In the embodiment shown in FIG. 1, the support layer comprises only a matrix resin. However, as long as the effects of the present invention are not impaired, other resins, fillers, surfactants, ultraviolet absorbers, antioxidants, anti-oxidants, etc. Additives such as fungicides, rust preventives, hygroscopic agents, coloring agents, phosphorescent substances and the like can also be contained. For example, when the luminescent color of the luminescent particle layer is bluish green, a red or pink fluorescent dye such as rhodamine 6G, rhodamine B, or a perylene dye may be contained. Also,
The other resin may have curability or tackiness as long as the transparency is not impaired.

The insulator material contained in the insulating layer of the insulating layer light-emitting layer, dispersion EL of
It may be an insulator particle, a high dielectric constant polymer or the like used for the device. In the embodiment of FIG. 1, the insulating layer is a coating layer formed from a paint formed by dispersing insulating particles in a high dielectric constant polymer. Examples of the insulating particles are, for example, insulating inorganic particles such as titanium dioxide, barium titanate, aluminum oxide, silicon oxide, silicon nitride, and magnesium oxide. As the high dielectric constant polymer, a polymer that can be used for the support layer can be used. The insulating layer can be provided, for example, on the back electrode or the luminescent particle layer by coating. When the insulating layer is a coating layer containing insulating particles and a high dielectric constant polymer, the mixing ratio thereof is such that the insulating particles are 1 to 100 parts by weight of the high dielectric constant polymer.
The range is 400 parts by weight, preferably 10 to 300 parts by weight, particularly preferably 20 to 200 parts by weight. If the amount of the insulating particles is too small, the insulating effect may be reduced and the light emission luminance may be reduced. Conversely, if the amount is too large, application of the paint may be difficult.

The thickness of the insulating layer is usually 2 to 1000 μm. In addition, as long as the insulating layer does not impair the insulating properties, fillers, surfactants, antioxidants, fungicides, rust inhibitors, moisture absorbents, coloring agents, phosphorescent substances, curable resins, adhesives, etc. Additives can also be included.

Light-Emitting Particle Layer The light-emitting particles of the light-emitting particle layer are particles that emit light when placed in an AC electric field. For example, phosphor particles used in the light-emitting layer of a dispersion-type EL element are used. it can. Phosphors are, for example, ZnS, CdZnS, ZnSSe, CdZ
A single fluorescent compound such as nSe, or a fluorescent compound of Cu,
It is composed of a complex to which auxiliary components such as I, Cl, Al, Mn, NdF ₃ , Ag and B are added.

The average particle diameter of the phosphor particles is usually 5 to 10
0 μm. Further, a phosphor in which a coating film is formed with glass, ceramics, or the like on the surface of a particle-shaped phosphor may be used. The thickness of the luminescent particle layer is usually from 5 to 500 μm. In addition, it is preferable that the luminescent particle layer is composed of a plurality of particles arranged substantially in a single layer, because the thickness of the EL element can be easily reduced.

Further, the luminescent particle layer may contain two or more kinds of luminescent particles. For example, a light-emitting layer with high whiteness can be formed by mixing at least two kinds of light-emitting particles that emit light of colors such as blue, blue-green, green, and orange, and have mutually independent spectra. . The ratio of the luminescent particles contained in the particles of the luminescent particle layer is preferably at least 40% by volume. If the content is less than 40% by volume, the effect of improving the emission luminance may be reduced. Luminance is maximized when the particles consist only of phosphor particles. Thus, a particularly preferred proportion of phosphor particles is 50
-100% by volume.

The luminescent particle layer may contain one or more particles (particles made of glass, coloring material, phosphor, polymer, inorganic oxide, etc.) other than the luminescent particles. For example, luminescent particles that emit blue-green light and a pink coloring material (rhodamine 6G,
And particles containing rhodamine B or the like) to form a light-emitting layer having high whiteness.

Formation of Light Emitting Layer A laminated structure composed of the supporting layer of the light emitting layer, the light emitting particle layer and the insulating layer is formed, for example, as follows. First,
The luminescent particle layer is formed on one surface of either the support layer or the insulating layer by an ordinary powder coating method. For example, while the support layer has fluidity, the electrostatic suction method,
The particles including the phosphor particles were sprayed on the support layer by a method such as a spraying method or a gravity scattering method to form a light-emitting particle layer in which the particles were partially or almost entirely embedded in the support layer. Thereafter, the fluidity of the support layer is lost, and the support layer and the particle layer are brought into close contact with each other. In order for the support layer to have fluidity, a method of keeping the coating layer formed from the coating material for the support layer containing a solvent in an undried state, the support layer at a temperature equal to or higher than the softening point or melting point of the resin for the support layer. Or a method in which a radiation-curable monomer is included in the coating material for the support layer. According to these methods, a solidifying operation (drying, cooling, or hardening) for losing the fluidity of the support layer is easy. Further, in the same manner, the luminescent particle layer can be formed on the insulating layer formed of the coating layer instead of the support layer.

The last layer (the other of the support layer and the insulating layer) is laminated on the luminescent particle layer formed as described above,
These form a laminated structure which is in close contact with each other. The last layer is applied with a paint comprising the material forming the layer,
It is preferable to solidify and laminate, or to laminate by a method of pressing a film made of a material forming the layer. According to these methods, it is possible to reliably form a contact structure in which no air bubbles exist at the respective interfaces of the support layer, the luminescent particle layer and the insulating layer.

In the embodiment shown in FIG. 1, the luminescent particle layer is composed of a plurality of particles arranged in a single layer and is in close contact with both the support layer and the insulating layer. However, as long as the effects of the present invention are not impaired, the light-emitting particle layer may be a multilayer particle layer, and a part or almost all of the light-emitting particle layer may be provided on one of the support layer and the insulating layer. May be completely buried. The point is that the luminescent particle layer is disposed between the support layer and the insulating layer, and it is only necessary that an adhesive structure can be formed in which substantially no air bubbles exist at the interface between any of the layers.

In the luminescent particle layer formed as described above, the material of the support layer or the insulating layer usually penetrates between the particles. In this case, the filling rate of the particles is usually at least 20% by volume, preferably at least 30% by volume, particularly preferably at least 40% by volume. This is because a decrease in the filling rate may cause a decrease in light emission luminance.

The term “particle filling rate” as used herein means that a layer composed of all the particles of the luminescent particle layer and a material other than the particles existing between the particles is defined as a particle relative to the total volume of the assumed layer. Is defined as a percentage of the total volume of further,
As long as the effects of the present invention are not impaired, the support layer and / or the insulating layer may be a laminate of two or more layers.

Manufacturing Method of EL Element Next, a manufacturing method according to an embodiment of the present invention, which is suitable for manufacturing the above-described EL element, will be described. First, a transparent base material having a transparent conductive layer laminated on its surface is prepared, a coating for forming a support layer is applied on the transparent conductive layer, and the particles including the phosphor particles are layered before the coating is dried. Spray and partially bury the layer of particles in the support layer, then dry the paint. This makes it possible to easily form a light-emitting particle layer that is partially buried in the support layer and adhered to the support layer.

The particles are usually 1 to 99%, preferably, 1 to 99% of the length in the vertical direction (the direction perpendicular to the plane of the support layer) of the particles (for example, the “diameter” for substantially spherical particles). 10-9
0%, particularly preferably 20-80%, is buried in the support layer. If the burial ratio is less than 1%, the particle layer may be damaged at the stage of forming the insulating layer. Conversely, if the burying ratio exceeds 99%, the particle layer may not be formed uniformly.

The coating thickness of the coating for forming the support layer is selected so that the dry thickness falls within the above range. The solid content of the coating material for forming the support layer is usually in the range of 5 to 80% by weight. The solvent used for the paint is selected from ordinary organic solvents so that the matrix resin can be uniformly dissolved. Mixing and kneading apparatuses such as a homomixer, a sand mill, and a planetary mixer can be used for preparing the coating. The coating operation includes a bar coater, roll coater, knife coater,
A coating device such as a die coater can be used. Drying conditions are
Although it depends on the type of the solvent of the paint and the solid content concentration, it is usually appropriately selected in the range of normal temperature (about 25 ° C.) to 150 ° C. for 5 seconds to 1 hour. The dispersion of the particles is carried out by the above-described method, usually within one minute after the coating material for forming the support layer is applied. Thereby, embedding of particles can be facilitated. The degree of drying of the coating material of the support layer at this time depends on the wettability between the particles and the support layer, but is usually in the range of 10 to 95% by weight, preferably 20 to 90% by weight in terms of solid content. is there.

Subsequently, a paint for forming an insulating layer is applied so as to cover the luminescent particle layer, and the paint is dried. As a result, the luminescent particle layer is buried in both the support layer and the insulating layer, and an adhesive structure in which substantially no air bubbles exist at the interface between any of the layers can be formed.

The coating thickness of the coating for forming the insulating layer is selected so that the dry thickness falls within the above range. The solid content of the coating material for forming the insulating layer is usually in the range of 5 to 70% by weight. The solvent used for the paint is selected from ordinary organic solvents so that the insulating material can be uniformly dissolved or dispersed. For the preparation and application of the paint, the same devices and equipment as in the case of the support layer forming paint can be used. The drying conditions depend on the type of the solvent of the paint and the solid content concentration, but are usually appropriately selected in the range of normal temperature (about 25 ° C.) to 150 ° C. for 5 seconds to 1 hour.

Finally, a back electrode layer is laminated on the insulating layer. The method described above can be used for forming the back electrode. However, a vacuum thin film forming method such as vapor deposition and sputtering is suitable for providing the insulating layer after drying efficiently and with good adhesion.

In the above-described manufacturing method, since each step is substantially the same as that of a normal sheet-like article, a large-area sheet having a high luminous luminance is used by using a normal sheet-like article manufacturing process. It is possible to manufacture the shape EL element with high productivity. Further, since it is not necessary to use a dispersion paint of the phosphor particles as in the related art, all problems caused by the dispersion paint can be solved.

As another method similar to the above method, first, an insulating layer paint is applied on a support including a back electrode,
Before it dries, luminescent particles are sprinkled, the particle layer is partially buried in the insulating layer, and then dried.Then, the support layer paint is applied and dried. There is also a manufacturing method including a series of steps of dry lamination, and the same effect as the above method can be obtained.

Use of EL Element The EL element of the present invention can be used as a backlight source for a liquid crystal display such as a liquid crystal instrument panel of an automobile. Also,
It can also be used as a light source for internally illuminated displays such as internally illuminated signboards, road signs, and decorative displays. For example, images such as characters and designs are provided on the surface of a light transmissive sheet, and the light transmissive sheet is used with the back surface of the sheet and the light emitting surface of the EL element facing each other. As the light transmitting sheet, for example, the same material as the above transparent substrate can be used, and its light transmittance is usually 2 or more.
0% or more. At this time, it is preferable that the back surface of the sheet and the light emitting surface of the EL element are in close contact with each other. In order to make them adhere to each other, a light-transmitting adhesive is used. Such an adhesive is
For example, an acrylic pressure-sensitive adhesive, an acrylic heat-sensitive adhesive, and the like.

Further, a light-transmitting sheet is used as the transparent substrate, a transparent conductive layer is directly provided on the back surface of the light-transmitting sheet, and a light-emitting layer is laminated on the conductive layer to form an EL-embedded display. You can also. Further, a prism type retroreflective sheet can be used as a light-transmitting sheet (or a transparent substrate). Combination with a retroreflective sheet
The retroreflective property and the self-luminous performance can be provided to the EL built-in display body.

Light emission of the EL element is usually performed by connecting a power source to two terminals provided on the transparent conductive layer and the back electrode layer and applying a voltage to the element. As the power source, for example, a battery such as a dry battery, a storage battery, or a solar battery is used, or an AC current supplied from a power transmission line is converted into an inverter (changing the magnitude of a voltage or a frequency or converting between AC and DC. apparatus)
Is supplied to the EL element via the. AC frequency is usually 50
It is in the range of -1000 Hz. The applied voltage is usually in the range of 3 to 200V.

Since the EL device of the present invention has high luminous efficiency,
It emits light with sufficient brightness (for example, 50 cd / m ² or more) even at a lower voltage (for example, 100 V or less) than the conventional dispersion type. When the EL element is used outdoors, it is preferable to use the EL element by covering it with a water-trapping film made of a polyamide resin or the like or a moisture-proof film made of a polytetrafluoroethylene film or the like.

[0042]

【Example】

(Example 1) Formation of EL element First, as a transparent substrate with an ITO layer, an ITO / PET laminated film manufactured by Oike Kogyo Co., Ltd. “Product number: TCF · KPC
300-75 (A) (thickness 75 μm, light transmittance 81
%)"It was used. In this film, on one surface,
A transparent conductive layer made of ITO (indium-tin-oxide) was laminated by a sputtering method. In addition, ITO
The thickness of the layer was 50 nm, and the surface resistance was 250 Ω / □. On the other hand, a high dielectric constant polymer (tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer “product number: THV200P” manufactured by 3M Company; a dielectric constant of 8 (1 k
Hz), light transmittance of 96%) and ethyl acetate,
It was uniformly dissolved using a homomixer to prepare a coating for forming a support layer. The solids content of the paint was about 25% by weight.

Next, the coating material for forming the support layer is applied on the transparent conductive layer of the transparent substrate, and the phosphor particles are dispersed substantially in a single layer before the coating material is dried. After being buried such that about 50% of the diameter was buried, the paint was dried.
The application of the paint was performed using a knife coater, and particles were sprayed immediately after the application. Drying conditions were about 65 ° C. for about 1 minute. The combined thickness of the support layer and the phosphor layer after drying was 40 μm. The phosphor particles are ZnS-based phosphor particles manufactured by OSRAM Sylvania Co., Ltd. “Product number: S-7”
28 (average particle diameter 23 μm) ”.

Subsequently, a coating material for forming an insulating layer was applied so as to cover the luminescent particle layer, and the coating material was dried to form an insulating layer. As a result, the luminescent particle layer was embedded in both the support layer and the insulating layer, and an adhesion structure in which substantially no air bubbles were present at the interface between any of the layers was formed. The coating for forming the insulating layer is made of a high dielectric constant polymer (the above-mentioned “article number:
THV200P ”), insulating particles (barium titanate manufactured by Kanto Chemical Co., Ltd.) and ethyl acetate were mixed in the same manner as the coating for forming the support layer. The weight ratio of polymer: insulator particles was 100: 80 and the solids content of the coating was about 38% by weight. The application of the paint was performed using a knife coater, and the drying conditions were about 65 ° C. and about 1 minute. The thickness of the laminate (light-emitting layer) composed of the support layer, the light-emitting particle layer, and the insulating layer after drying was 45 μm.

Finally, a back electrode layer made of aluminum was laminated on the insulating layer by using a vacuum evaporation method to form a film-like EL device of this example. In addition, the vacuum evaporation apparatus used here is "Model number: EBV-6" manufactured by ULVAC Corporation.
DA ”, the pressure in the chamber is 10 ⁻⁵ Torr or less,
The deposition was performed for 5 seconds.

Light Emission of EL Element A terminal was provided on each of the transparent conductive layer and the back electrode layer of the EL element of this example (cut into a square shape with a plane size of 100 mm × 100 mm), and a power supply device (Kikusui Electronics Corporation)
(Product number: PCR500L), and two sets of conditions (condition A: 100 V, 400 Hz, condition B: 120)
(V, 600 Hz), an AC voltage was applied, and uniform light emission was obtained under both conditions.

The EL element was placed in a dark box, and the light emission luminance at a point 1 m vertically away from the surface of the transparent base material was measured using a luminance meter “LS110” manufactured by Minolta Co., Ltd. Table 1 shows the results.

Comparative Example 1 An EL device of this example was formed in the same manner as in Example 1 except that a “dispersion type” light emitting layer was used. The "dispersed" light emitting layer was formed as follows. The same high dielectric constant polymer (100 parts by weight), phosphor particles (150 parts by weight) and ethyl acetate as in Example 1 were mixed,
The coating material for forming a light emitting layer was prepared by uniformly dispersing using a homomixer. The solids content of the paint was about 45% by weight. The coating was applied on the transparent conductive layer of the transparent substrate using a knife coater, and dried at about 65 ° C. for about 1 minute. The thickness of the light emitting layer after drying was 30 μm. The light emission luminance of the EL element of this example was measured in the same manner as in Example 1. Table 1 shows the results.

(Example 2) The phosphor particles were made of ZnS phosphor particles manufactured by OSRAM Sylvania Co., Ltd.
An EL device of this example was formed in the same manner as in Example 1, except that "-723" was used. Further, the emission luminance of the EL element of this example was measured in the same manner as in Example 1. Table 1 shows the results.

(Example 3) Except that the high dielectric constant polymer of the support layer and the insulating layer was changed to a cyanoresin “product number: CR-M (dielectric constant = 18 (1 kHz))” manufactured by Shin-Etsu Chemical Co., Ltd. The EL element of this example was formed in the same manner as in Example 1.
Further, the emission luminance of the EL element of this example was measured in the same manner as in Example 1. Table 1 shows the results.

[0051]

[Table 1]

The moisture resistance of the EL devices of Example 2 and Comparative Example 1 was evaluated as follows. After aging the EL device for 12 hours under the conditions of 65 ° C./95% RH, an AC voltage was applied under the above condition B to emit light, and the luminance was measured. The retention ratio of the luminance after aging to the luminance before aging is 90% in Example 2,
In Comparative Example 1, it was 63%. Thereby, E of the present invention
It was shown that the L element had higher moisture resistance than the EL element having the dispersed light emitting layer.

[0053]

According to the present invention, the filling rate of the luminescent particles in the luminescent layer can be easily increased, and about 2% of the dispersion type luminescent layer can be obtained.
An EL element with improved emission luminance more than twice can be provided.
Further, according to the present invention, there is no need to use a dispersion paint for the light emitting layer, a high light emission luminance, a large area sheet-like EL element,
It can be manufactured with high productivity. According to the production method of the present invention, for example, a width of 25 to 200 cm and a length of 100 to
Starting from a roll of 20,000 m of transparent base material, a transparent conductive layer, a support layer, a luminescent particle layer, an insulating layer, and a back electrode are successively laminated to mass-produce a large-area sheet-like EL element. It is possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of an EL element of the present invention.

[Explanation of symbols]

1: transparent substrate, 2: transparent conductive layer, 3: support layer, 4: luminescent particle layer, 5: insulating layer, 6: back electrode, 7: luminescent particles,
8: Light emitting layer

Claims (2)

[Claims] 1. a) a transparent substrate (1), b) a transparent conductive layer (2) disposed on the back surface of the transparent substrate (1), c) a phosphor particle (7) and a matrix resin, An electroluminescent device comprising: a light emitting layer (8) disposed on the back of the transparent conductive layer (2); and d) a back electrode (6) disposed on the back of the light emitting layer (8). 8) includes (c-1) a matrix resin, a transparent support layer (3) disposed on the side of the transparent conductive layer (2), and (c-2) an insulator material. (C-3) light emission comprising light emitting particles (7) embedded in both the support layer (3) and the insulating layer (5); and (c-3) an insulating layer (5) disposed on the electrode (6) side. An electroluminescent device comprising a particle layer (4). 2. A transparent substrate (1), a transparent conductive layer (2) disposed on the back surface of the transparent substrate (1), and a transparent conductive layer (2) including luminescent particles (7) and a matrix resin. In a method for manufacturing an electroluminescent device having a light-emitting layer (8) disposed on a back surface and a back electrode (6) disposed on a back surface of the light-emitting layer (8), i) the transparent conductive layer (2) A transparent substrate (1) laminated on one surface is prepared, and ii) a paint for forming a support layer (3) containing a matrix resin is applied on the transparent conductive layer (2), and the paint is applied. Before the particles are solidified, the particles including the phosphor particles (7) are sprayed in a layer form, and the particles are partially embedded in the paint. Then, the paint is solidified, and the transparent support layer (3) and the support Forming a luminescent particle layer (4) in close contact with the layer (3); iii) an insulating material on the luminescent particle layer (4). A coating for forming an insulating layer (5) comprising: coating the coating and solidifying the coating to form an insulating layer (5) in close contact with the luminescent particle layer (4); iv) On the insulating layer (5) A back electrode layer (6) is laminated on the
A manufacturing method comprising a step.