JPH08185981A - White light emitting el lamp - Google Patents

Abstract

PURPOSE: To provide a white light emitting EL lamp excellent in fire resistance by dispersing a transparent resin particle of a specified particle size colored with a fluorescent dye into a light emitting layer. CONSTITUTION: This white fight emitting EL lamp has a light emitting layer arranged between two electrodes at least one of which is transparent. A transparent colored resin particle of a particle size of 10-50μm colored with a fluorescent dye having a complementary color relation with the emitting color of a phosphor powder in the light emitting layer is dispersed into the light emitting layer. The transparent colored resin particle is preferably obtained by the suspension polymerization of the starting monomer of the transparent resin with the fluorescent dye. As the fluorescent dye, perylene dye is preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a white light emitting EL lamp, and more particularly, to a white light emitting EL lamp having excellent light resistance.

[0002]

2. Description of the Related Art An EL lamp has a structure in which a light emitting layer made of a composition of an organic high dielectric binder and an electroluminescent phosphor powder is disposed between two electrodes at least one of which is transparent. By the way, since there is no phosphor powder that emits white light, a white light emitting EL lamp is disclosed in, for example,
As proposed by Japanese Patent No. 4540, this is achieved by disposing a film colored with a fluorescent dye having a complementary color relationship with the emission color of the phosphor powder on the emission layer (phosphor layer).

[0003]

However, a white light emitting EL lamp in which a colored film is disposed on a light emitting layer (phosphor layer) has a disadvantage that light resistance is poor. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a white light emitting EL lamp having excellent light resistance.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have achieved the above object by dispersing transparent resin particles having a specific particle diameter colored by a fluorescent dye in a light emitting layer. We have found that it can be easily achieved. The present invention has been completed based on such knowledge, and the gist of the present invention is to arrange a light emitting layer between two electrodes, at least one of which is transparent, and to include the light emitting layer in the light emitting layer. A white light emitting EL lamp characterized in that transparent colored resin particles colored with a fluorescent dye having a complementary color relationship with the emission color of the phosphor powder in the layer and having a particle size of 10 to 50 μm are dispersed.

Hereinafter, the present invention will be described in detail. As the organic high dielectric binder, a cyanoethylated compound or the like is used, and as the electroluminescent phosphor powder, a zinc sulfide-based phosphor (ZnS: Cu, C1) is usually used. The zinc sulfide-based phosphor is an electroluminescent phosphor using zinc sulfide (ZnS) as a base material, copper (Cu) as an activator, and chlorine (C1) as a co-activator. In addition to chlorine, bromine (Br) and aluminum (Al) are used.

[0006] The transparent colored resin particles are preferably spherical monodisperse particles having a uniform particle diameter, and such monodisperse particles can be obtained by suspension polymerization of a raw material monomer of a transparent resin and a fluorescent dye. . As the raw material monomer, styrene, methyl methacrylate, vinyl acetate, and the like are preferably used. As the fluorescent dye, a fluorescent dye having a complementary color relationship with the emission color of the phosphor powder is used. For example, since the above-mentioned electroluminescent phosphor emits blue-green (400 to 600 nm), it is 450 to 55 nm.
A fluorescent dye having a maximum absorption wavelength at 0 nm is used.
As such a fluorescent dye, a perylene dye is particularly suitable. As commercially available perylene dyes, for example, “Lu
mogen F Red 200 "," Lumogen
F Red 300 ".

The suspension polymerization is carried out according to a known formulation, and a water-soluble polymer such as polyvinyl alcohol and carboxymethyl cellulose is used as a dispersion stabilizer.
Benzoyl peroxide, lauroyl peroxide, 2,2'-azobisisobutyronitrile and the like are used as the initiator. The ratio between the raw material monomer and the fluorescent dye is usually 0.5 to 5 as the ratio of the fluorescent dye to the raw material monomer.
% By weight.

In the present invention, the transparent colored resin particles must have a particle size in the range of 10 to 50 μm, preferably 20 to 40 μm. When the particle size of the transparent colored resin particles is smaller than the above range, the color is rapidly faded and the effect of improving the light resistance is not sufficient. On the other hand, when the particle size of the transparent colored resin particles is larger than the above range, lamination failure of the transparent electrode is caused in the manufacturing process of the white EL lamp, and a white EL lamp having uniform luminous ability cannot be obtained. In addition, the particle size of the transparent colored resin particles can be adjusted by a stirring force or the like during suspension polymerization.

The light emitting layer of the white light emitting EL lamp of the present invention comprises:
It is composed of an organic high dielectric binder, electroluminescent phosphor powder, and transparent colored resin particles. The ratio of the electroluminescent phosphor powder to the organic high dielectric binder is usually 1.
The range is 5 to 5.0% by weight, preferably 3.0 to 3.5% by weight, and the use ratio of the transparent colored resin particles to the organic high dielectric binder is usually 3 to 30% by weight, preferably 5 to 30% by weight. It is in the range of 17% by weight.

Usually, a transparent conductive film (ITO film) is used as the transparent electrode, and an aluminum foil is preferably used as the back electrode. Preferably, a reflective insulating layer is interposed between the back electrode and the light emitting layer. The reflective insulating layer is composed of a composition of an inorganic high dielectric powder and an organic high dielectric binder. As the inorganic high dielectric powder, titanium oxide or barium titanate is used, and as the organic high dielectric binder, a cyanoethylated compound of a hydroxyl group-containing compound such as poval or pullulan is used.

The white light emitting EL lamp of the present invention can be manufactured by the following method. First, a reflective insulating layer paste containing an organic high dielectric binder and an inorganic high dielectric powder, and a light emitting layer paste containing an organic high dielectric binder, an electroluminescent phosphor powder, and transparent colored resin particles are prepared. . Then, a reflective insulating layer paste is applied on the back electrode and dried by heating to form a reflective insulating layer, and then a light emitting layer paste is applied and heated and dried to form a light emitting layer. Next, a transparent conductive film is thermally laminated on the light emitting layer to form a transparent electrode.

The white light emitting EL lamp of the present invention is practically used after being covered with a moisture-proof film. Usually, a laminated film composed of a fluorinated resin film and a heat sealable transparent sealant film is used as the moisture-proof film. Particularly, as the fluorinated resin film, polychlorinated ethylene trifluoride (PCTFE) is preferably used, and as the transparent sealant film, an ethylene-vinyl acetate copolymer (EVA) film, unstretched polypropylene (CPP) A film, an ethylene-ethyl acrylate (EEA) film, an ethylene-acrylic acid copolymer (EAA) film, and the like are used.

The lamination of the fluorinated resin film and the transparent sealant film is performed by using a transparent adhesive such as urethane, acrylic or polyester. And
The entire surface of the back electrode and the transparent electrode is sealed by the transparent sealant film of the moisture-proof film.

[0014]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention.

Synthesis Example 1 (Synthesis of transparent colored resin particles) 250 g of water and polyvinyl alcohol 1 were placed in a reactor equipped with a stirrer.
After charging 2.5 g and stirring at a temperature of about 75 ° C. for about 2 hours, the mixture was cooled to 25 ° C. On the other hand, “240” and “30” of “Lumogen F Red” were added to 37.5 g of styrene.
0 "and 0.25 g of each, stirred at 70 ° C. for about 15 minutes, cooled to 25 ° C., and then 12.6 g of divinylbenzene and a polymerization initiator (t-Butylperoxy-2-ethylhex) were added.
A mixture of 50% by weight of anoate and 50% by weight of diluent) 0.5
1 g was added, and the resulting mixture was added to the aqueous polyvinyl alcohol solution in the reactor with a stirrer described above, and a polymerization reaction was performed under a nitrogen atmosphere.

In the polymerization reaction, first, stirring is performed for 20 minutes while the rotation speed of the turbine blade of the stirrer is kept constant, during which 0.7 ml of a 1% by weight solution of a surfactant "Neogen" is added. For 2 hours at a temperature of
C. for 90 minutes. After the reaction, the transparent colored resin particles were taken out by standing overnight, washed with water by stirring with a stirrer three times, and then dried at 50 ° C. And
After dispersing the secondary particles, transparent colored resin particles having a predetermined particle size were recovered by a sieve. By changing the rotation speed of the turbine blade of the stirrer, three kinds of transparent colored resin particles having different average particle sizes were synthesized.

Example 1 and Comparative Examples 1-2 After 50 g of cyanoethylated pullulan and 50 g of cyanoethylated sucrose were dissolved in 150 g of DMF, 464 g of barium titanate powder was dispersed to prepare an insulating paste. This was applied to a 100 μm aluminum foil by screen printing, and dried at 120 ° C. for 2 hours to form a reflective insulating layer.

Next, 34 g of cyanoethylated pullulan and 34 g of cyanoethylated saccharose were mixed with 150 g of DMF.
After that, 223 g of zinc sulfide-based phosphor powder (“Type728” manufactured by GTE, average particle size: 31 μm) and 6.7 g of transparent colored resin particles were dispersed therein to prepare a composition for forming a light emitting layer. This was applied on the insulator layer by screen printing and dried at 120 ° C. for 2 hours to form a light emitting layer.

Next, an ITO film was thermally laminated on the light emitting layer to form a structure in which the insulator layer and the light emitting layer were interposed between the electrodes. After connecting the lead wires to these two electrodes, the electrodes were sealed with a trifluorinated chlorinated polyethylene film to obtain a white light emitting EL.
Got the lamp. The thickness of each layer of the white light emitting EL lamp of each example is as shown in Table 1.

[0020]

[Table 1]

In order to evaluate the light resistance of the white light emitting EL lamp, an outdoor exposure test was performed for 3000 hours.
An AC voltage of 00 V-400 Hz was applied, and evaluation was performed using the XYZ color system. Table 2 shows the value of ΔX before and after outdoor exposure. Note that the change in the Y value was determined in Example 1 and Comparative Examples 1 and 2.
Were small.

[0022]

[Table 2]

[0023]

The white light emitting EL lamp of the present invention described above exhibits excellent light resistance, and is particularly suitable for outdoor signboards and backlights (auxiliary light sources) of liquid crystal display elements.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Jun Nakamura 34 Takayama, Onahama, Iwaki-shi, Fukushima Japan Chemical Research Laboratory

Claims (3)

[Claims] 1. A light-emitting layer is provided between two electrodes, at least one of which is transparent. The light-emitting layer contains a fluorescent dye complementary to the emission color of the phosphor powder in the light-emitting layer. A white light-emitting EL lamp characterized by being dispersed with transparent colored resin particles having a particle diameter of 10 to 50 μm. 2. The white light emitting EL lamp according to claim 1, wherein the transparent colored resin particles are obtained by suspension polymerization of a raw material monomer of the transparent resin and a fluorescent dye. 3. The white light emitting EL lamp according to claim 1, wherein the fluorescent dye is a perylene dye.