JPH04289690A - Manufacture of el illuminant - Google Patents

Abstract

PURPOSE:To provide an illuminant excellent in brightness and a life and also having stable quality such as uniform luminance in the case of a luminous color of an EL illuminant being changed. CONSTITUTION:A filter substrate 2, in which one side of a supporting base material 22 is provided with an SiO2 layer 21 where a phosphor dye is solidified, and the other side is provided with a transparent electrode layer 23, is provided with a luminous layer 3 containing diffused phosphor and a rear electrode layer 5 in order to manufacture an EL illuminance. The EL illuminant excellent in the thinness can be formed. Also in case the luminous layer is formed by a sol-gel method, a luminous color can be changed while being able to use various kinds of phosphor dyes and to obtain many kinds of luminance.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an EL light emitting material that is excellent in uniform luminescence, brightness, and long life.

0002

BACKGROUND OF THE INVENTION Conventionally, as a method for producing an EL luminescent material in which the luminescent layer containing a dispersed phosphor changes the luminescent color, a method of mixing a fluorescent pigment into the luminescent layer has been known.

However, fluorescent pigments tend to aggregate,
Further, due to the difference in specific gravity with the phosphor, it is difficult to disperse and mix the phosphor uniformly, and the quality tends to vary, making it difficult to emit light uniformly. Furthermore, when a fluorescent pigment is mixed to emit white light, there is a problem that the brightness and lifespan are lower than when emitting white light (blue-green) without mixing a fluorescent pigment.

0004

[Problems to be Solved by the Invention] The present invention provides a method for producing an EL light emitting material that has excellent brightness and life, and has stable quality such as uniform luminescence when changing the natural luminescent color based on the phosphor used. The challenge is to develop

[0005]

[Means for Solving the Problems] The present invention provides S.
EL, characterized in that a filter substrate is provided with an iO2 layer and a transparent electrode layer on the other side, and a light emitting layer containing a dispersed phosphor and a back electrode layer are provided on the side of the transparent electrode layer.
A method for manufacturing a light emitting body is provided.

[0006]

[Action] SiO with fluorescent dye immobilized by liquid phase precipitation method
By interposing two layers to change the luminescent color, fluorescent dyes can be contained in a uniformly dispersed state, and a dense SiO2 layer can be formed, which improves moisture resistance, weather resistance, etc. It can be made to have excellent durability. Furthermore, since the SiO2 layer has excellent water-blocking properties, it becomes possible to omit the water-trapping layer and to make the moisture-proof layer thinner.

Furthermore, various fluorescent dyes can be immobilized,
The light based on the light-emitting layer having the same structure can be varied in many ways.

[0008]

EXAMPLE An EL light emitter according to the manufacturing method of the present invention is illustrated in FIG. 2 is a filter substrate, 21 is a SiO2 layer with fixed fluorescent dye, 22 is a support base material, 23 is a transparent electrode layer, 3 is a light emitting layer, and 5 is a back electrode layer. Note that 1 is a moisture-proof layer, 4 is an insulating layer, and 6 is a water-trapping layer.

In the present invention, a filter substrate is used. The filter substrate has a SiO2 layer on which a fluorescent dye is immobilized using a liquid phase precipitation method on one side of a transparent support base material.
It consists of a transparent electrode layer provided on the other side. There is no particular limitation on the order in which the SiO2 layer and the transparent electrode layer are provided.

Although a glass plate or the like may be used as the transparent supporting substrate, plastic films are generally used. There are no particular limitations on the type of plastic.

[0011] The SiO2 layer on which the fluorescent dye is fixed, which is provided on one side of the transparent support base material, is formed by a liquid phase deposition method (LPD method). That is, for example, a fluorescent dye is added to an aqueous solution of hydrofluorosilicic acid saturated with silica, an initiator such as a boric acid aqueous solution is added thereto, the support substrate is immersed, and the dye is dyed on the support substrate at room temperature or the like. SiO2 containing fluorescent dye
This can be done by a method such as growing a layer by precipitation.

The thickness of the SiO2 layer may be determined as appropriate, but is generally 100 μm or less, particularly 5 to 60 μm. As the fluorescent dye, a dye that can be changed to a desired luminescent color, such as rhodamine 6G, auramine, and rocket red, is used.

On the other hand, the transparent electrode layer can be formed on the other surface of the support substrate by, for example, vapor-depositing a transparent conductivity-imparting agent such as an oxide of indium or tin, or by depositing a transparent conductivity-imparting agent in a resin binder. This can be carried out by applying a transparent conductive paint or the like which is added to. The above SiO2
In the case of a method in which layers are formed on both sides, such as the dipping method or the above-mentioned vapor deposition method, one side is masked if necessary.

[0014] Application of the transparent conductive paint etc. may be carried out by any suitable method such as screen printing, casting, doctor blading, or roll coating.

Examples of resin binders in transparent conductive paints include cyanoethyl cellulose, cyanoethyl sucrose, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene,
Tetrafluoroethylene/hexafluoropropylene copolymers, vinylidene fluoride copolymers, and the like are preferably used.

[0016] As the copolymer component with vinylidene fluoride in the vinylidene fluoride copolymer, one such as tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, etc.
A species or two or more species may be used. In preparing the coating solution, an appropriate organic solvent such as cellosolve acetate, dimethylformamide, or methyl ethyl ketone may be used.

A current collecting band made of a coating layer of a resin paste containing conductive powder such as silver powder or carbon is provided on the transparent electrode layer, if necessary. The current collecting band is for suppressing bias in the voltage applied to the transparent electrode layer via the terminal type lead electrode. The current collecting band is usually provided in a band shape on a part of the transparent electrode layer.

A light-emitting layer containing a dispersed phosphor and a back electrode layer are provided on the transparent electrode layer side of the filter substrate. The method of providing them is arbitrary. Examples include a method in which the necessary layers are sequentially coated or laminated on a transparent electrode layer, a method in which an integrated body having a light-emitting layer and a back electrode layer is formed in advance, and this is bonded to a filter substrate. .

The light-emitting layer containing the phosphor dispersed therein can be formed, for example, by adding the phosphor to a resin binder and coating it, or by a sol-gel method. As the phosphor, for example, zinc sulfide or cadmium zinc sulfide activated with copper, manganese, aluminum, silver, chlorine, boron, etc., and oxides such as rare earth activated yttrium oxide are generally used. The average particle size of the phosphor is 10μ
m or more, preferably 15 to 40 μm. Further, the volume occupancy of the phosphor in the light emitting layer is generally 30 to 80%.

[0020] The light-emitting layer containing dispersed phosphor can be formed by the sol-gel method, for example, by the following method. That is, an organometallic compound such as a metal alkoxide such as tetraethoxysilane is dissolved in ethanol, isopropanol, etc., a catalyst such as an acetic acid aqueous solution is added to the solution, and heated as necessary to cause a hydrolysis reaction, polycondensation reaction, etc. Generate a high molecular weight sol.

Next, the solvent such as alcohol in the polymerized sol is replaced with propylene carbonate or the like to stop the sol-gel reaction, and then a phosphor is added to the polymerized sol as a binder. Examples include a method in which the dispersion is applied to a transparent electrode layer, a back electrode layer, etc., and then heat-treated.

[0022] In the method of forming a luminescent layer using the sol-gel method, until now it has not been possible to add fluorescent pigments to the luminescent layer due to thermal decomposition problems during heat treatment, and therefore it has not been possible to change the luminescent color to white or the like. Therefore, the method of the present invention can be particularly preferably applied.

The back electrode layer can be formed, for example, by applying a conductive paint or by using a suitable metal foil such as aluminum foil.

In the present invention, formation of, for example, a moisture-proof layer, a water-trapping layer, a current collecting band, an insulating layer, a lead electrode, etc. is optional and can be done in accordance with conventional methods.

The moisture-proof layer surrounds the outside of the EL light emitter to prevent moisture from entering. The thickness of the moisture-proof layer may be determined as appropriate, but from the viewpoint of reducing the thickness of the EL light emitter, a thickness of 50 to 500 μm is appropriate. An appropriate plastic film may be used to form the moisture barrier layer. Preferably, a plastic film with low water absorption and moisture permeability is used.

Examples of plastic films that can be preferably used to form the moisture-proof layer include polychlorotrifluoroethylene or its copolymer, polyvinylidene chloride, vinyl chloride/vinylidene chloride copolymer, oriented polypropylene, high-density polyethylene, Examples include films made of tetrafluoroethylene/hexafluoroethylene copolymer, fluoroethylene/propylene copolymer, polyethylene terephthalate, ethylene/tetrafluoroethylene copolymer, and the like.

The water-trapping layer is usually provided inside the moisture-proof layer, and is provided as necessary to prevent moisture from entering the light-emitting layer. For forming the water-absorbing layer, a water-absorbing plastic that is insoluble in water but exhibits the property of absorbing and trapping moisture to swell is preferably used. Among these, those having a water absorption capacity of 5 times or more, particularly 10 times or more of their own weight are preferred.

Examples of water-absorbing plastics include carboxyl groups, sulfonic groups, phosphoric acid groups, quaternary ammonium salts, amino groups, imino groups, ionizable groups such as pyridium groups, or salts thereof and/or hydroxyl groups, Examples include natural or synthetic hydrophilic and water-insoluble polymers having nonionic hydrophilic groups such as ether groups, chain or cyclic amide groups, and nitrile groups.

Specific examples of water-absorbing plastics include polyacrylamide, a blend polymer of polyacrylamide and polyolefin, a copolymer of acrylic acid or its salt and divinylbenzene, and a copolymer of acrylonitrile, vinyl chloride, and ethylene monomer. Examples include an alkali hydrolyzate of a copolymer, an alkali hydrolyzate of a copolymer of acrylonitrile, vinylidene chloride, and an ethylene monomer, and the like.

Furthermore, formaldehyde-crosslinked products of acrylamide-based copolymers, acid condensates of polyacrylic acid and polyvinyl alcohol, epichlorohydrin-crosslinked products of polyvinyl alcohol, and formaldehyde-crosslinked products of acrylonitrile-based polymers hydrolyzed with alkali. , a phosphoric acid condensate of polyvinyl alcohol, and a copolymer of 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate.

Furthermore, a copolymer of 2-methyl-5-vinylpyridine and N,N'-methylenebisacrylamide, a copolymer of N,N'-dimethylaminoethyl methacrylate and N,N'-methylenebisacrylamide, Polymer, copolymer of N-vinyl-2-pyrrolidone and ethylene glycol dimethacrylate, crosslinked product of polyoxyethylene by radiation irradiation, acidic heating condensate of starch, saponified product of starch-acrylonitrile graft copolymer,
Also included are dried copolymers of vinyl esters and ester-based unsaturated carboxylic acids or derivatives thereof, isobutylene-maleic acid copolymers, and the like.

The water-absorbing layer can be formed by applying a water-absorbing plastic solution or laminating a water-absorbing plastic film. The thickness is 2
The thickness is generally 0 to 300 μm, but is not limited thereto.

The insulating layer can be formed by applying an insulating resin, laminating an insulating film, or the like. The insulating layer may contain high dielectric constant fine particles such as barium titanate, lead titanate, zirconium titanate, titanium oxide, zinc sulfide, and silicon carbide, as in the light emitting layer.

By the way, a transparent conductive paint made of a cellosolve acetate solution of a vinylidene fluoride copolymer containing ITO dispersed therein was coated on one side of a supporting base material made of a polyester film with a thickness of about 5 μm. After forming a transparent electrode layer and partially applying a resin paste containing silver powder on it to form a current collecting band with a width of 2 mm, masking was performed with a resist resin, and liquid phase deposition was performed on the other side of the supporting base material. A filter substrate was obtained by forming a 30 μm thick SiO2 layer on which Rhodamine 6G was immobilized by the method.

Next, after attaching a lead electrode on the transparent electrode layer of the filter substrate, cellosolve acetate, which is a vinylidene fluoride copolymer containing dispersed phosphor made of zinc sulfide activated with copper and aluminum, is added. A solution is applied to form a luminescent layer with a thickness of approximately 50 μm, and a cellosolve acetate solution of a vinylidene fluoride copolymer containing barium titanate is applied on top of the luminescent layer to form an adhesive layer with a thickness of approximately 15 μm which also serves as an insulating layer. A back electrode layer made of aluminum foil with a thickness of 20 μm was laminated therebetween, and lead electrodes were attached.

Next, a polyacrylamide solution was applied to the back surface of the back electrode layer in the laminate to form a water absorption layer with a thickness of 50 μm.
A 0 μm PVDC film was placed and its periphery was adhered to form a sealed structure to obtain an EL light emitting body.

After measuring the luminance of the EL light emitter, it was heated at 40° C. and 90% RH, and at 100 V and 400 volts.
As a result of measuring the brightness again after leaving it under the Hz driving condition for 100 hours, the brightness maintenance rate (initial brightness 100
relative brightness) was 95%.

For comparison, instead of adding the SiO2 layer,
As a result of examining the brightness maintenance rate of the EL emitter using a luminescent layer containing rhodamine 6G as described above, it was found that the luminance retention rate was 80.
%Met.

[0039]

[Effects of the Invention] According to the present invention, since the SiO2 layer with fixed fluorescent dye is interposed inside the EL luminescent material, the luminescent color can be changed even in the case of a luminescent layer formed by the sol-gel method. It is possible to use various fluorescent dyes, and it is possible to obtain various types of light emission based on the light emitting layer having the same structure, and white light can also be easily obtained. Further, an EL light emitting body having excellent uniformity of light emission, brightness, weather resistance, etc. and long life can be obtained. Furthermore, by using the filter substrate, it is possible to reduce the number of support base materials required for providing the functional layer, and it is possible to obtain an EL light emitting body with excellent thinness.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an EL emitter according to an embodiment of the invention.

[Explanation of symbols]

1: Moisture barrier layer 2: Filter board 21: SiO2 layer 22: Support base material 23: Transparent electrode layer 3: Luminescent layer 4: Insulating layer 5: Back electrode layer 6: Water trapping layer

Claims (1)

[Claims] Claim 1: A filter substrate comprising a SiO2 layer on which a fluorescent dye is immobilized by a liquid phase deposition method is provided on one side of a transparent support base material and a transparent electrode layer on the other side, and a phosphor is dispersed and contained therein. A method for manufacturing an EL light emitting body, characterized in that a light emitting layer and a back electrode layer are provided on the transparent electrode layer side.