JPH05226076A - El emitter - Google Patents

Abstract

PURPOSE:To provide an EL emitter, which is not easily heated even in the case it is larger than A4 size, which does not easily generate partial deviation in the temperature, and which has excellent homogeneous emission and brightness over the whole body, and does not easily generate uneven emission or warping. CONSTITUTION:An emission layer, in which phosphor is included in a dispersed form, is formed between a transparent electrode layer 3 provided with a bus bar 2, which is provided around the transparent electrode layer 3, while power receiving parts 1 are arranged at least at two points with an interval. At least one disconnected part is formed on the bus bar 2 when necessary, and the bus bar 2 is broadened by changing the width in steps or continuously as it goes further away from the power receiving part. An EL emitter thus provided is excellent in the brightness and the maintenance of the brightness, and in the emission life and homogeneity of the emission. A conventional technique is utilized to easily achieve large area of the EL emitter only by changing the form of the bus bar and the number of arrangement of the power receiving part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EL light-emitting body capable of obtaining a large area body with less variation in light emission and less heat generation.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a fluorescent bar is formed between a rear electrode layer and a transparent electrode layer 3 in which a power receiving portion 1 composed of one lead electrode is provided on a bus bar 2 having a substantially L shape. An EL luminescent material provided with a luminescent layer containing a dispersed body has been known.
Such an EL light-emitting body emits an electric field by applying an alternating current to the light-emitting layer through the transparent electrode layer and the back electrode layer, and variations in the supplied power cause uneven light emission. Therefore, the bus bar is provided for the purpose of uniformly and quickly supplying electric power to the entire surface of the transparent electrode layer.

However, when a large area body such as an A4 size which can be used as a backlight of a liquid crystal display device is formed in the conventional bus bar form, the light emission greatly varies and a large temperature is generated at both ends of the substantially L-shaped bus bar. It was found that there was a difference, and there was a problem that did not occur in the case of a size such as a business card size that fits in the hand so far. Occurrence of a partial temperature difference in the EL light-emitting body causes unevenness in light emission and warpage. By the way 50
In the case of a large size of 0 mm × 300 mm, the difference in heat generation temperature at both ends of the above-mentioned L-shaped bus bar reaches about 40 ° C.

[0004]

According to the present invention, even when a large-area body of A4 size or more is generated, it is difficult to generate heat and a partial temperature difference is unlikely to occur. The challenge is to develop an EL light-emitting body that is less likely to cause unevenness and warpage.

[0005]

According to the present invention, a light emitting layer containing a fluorescent substance dispersed therein is provided between a transparent electrode layer provided with a bus bar and a back electrode layer, and the bus bar is a transparent electrode layer. E, which is attached to the periphery of the vehicle and has a power receiving portion arranged at two or more places at intervals.
An L light-emitting body is provided, and at least one dividing portion is formed on the bus bar as needed, or the width of the bus bar is changed stepwise or continuously so that the bus bar becomes wider as the distance from the power receiving portion increases. It is a thing.

[0006]

With the above structure, the electric power can be distributed and supplied through the electric power receiving portions provided at two or more places, the shared electric power supply path can be shortened, the heat generation due to the electric resistance of the bus bar can be suppressed, and the electric power can be evenly supplied. Can be changed. In addition, electric power can be efficiently supplied to the entire inner region of the transparent electrode layer via the bus bar provided around the transparent electrode layer.

In the above case, by forming the dividing portion in at least one position of the busbar, it is possible to cut the unnecessary current in the busbar path portion where the dividing portion intervenes while achieving the power supply to the transparent electrode layer. The heat generation can be suppressed, and the power supply to the other busbar path portion can be prioritized to increase the current in that portion. Further, by making the width of the bus bar wider as it goes farther from the power receiving portion, it is possible to reduce the resistance value and facilitate the flow of current, and improve the power supply to the terminal portion.

[0008]

EXAMPLES FIG. 1, FIG. 2 and FIG. 3 exemplify the attachment modes of other bus bars in the EL light-emitting body of the present invention. Further, FIG. 4 shows an example of forming an EL light emitting body. Reference numeral 1 is a power receiving portion composed of a lead electrode, 2 is a bus bar, 3 is a transparent electrode layer, 4 is a light emitting layer, and 6 is a back electrode layer. In addition, 5 is an insulating layer.

In FIG. 1, the bus bar 2 is a transparent electrode layer 3
It is attached to the periphery of and has different widths in stages. The narrowly formed path 21 has a dividing portion in the middle, and has one power receiving portion 1 in each of the portions separated via the dividing portion. The path 22 formed continuously with the path 21 is formed wider than the path 21. Further, the path 23 located farthest from the power receiving unit 1 has a wider width and is formed continuously with the path 22.

On the other hand, in FIG. 2, a bus bar 2 having a substantially L-shape is provided on the periphery of the transparent electrode layer 3 with the diagonal line as a reference and in a separated state so that a divided portion is formed. Each bus bar 2 is composed of a narrow path 24 and a wide path 25, and has one power receiving unit 1 at the end of the path 24.

On the other hand, in the bus bar 2 in FIG. 3, the paths 26 formed to have the same width are continuously provided on the four sides and are attached around the transparent electrode layer 3, and the inside surrounded by the paths 26 has a narrow width. The routes 27 and 28 are attached in a grid arrangement. Then, one power receiving unit 1 is provided at each of four corners of the quadrangle formed by the path 26.

In the present invention as in the above-mentioned embodiments, the bus bar may be provided around the transparent electrode layer in any desired form. The bus bar may be formed by an appropriate method such as a method of applying a resin paste containing a conductive powder such as silver powder or carbon, a method of adhering a metal foil with a conductive adhesive or the like.

When a dividing portion is provided in the path of the bus bar,
The position and the number of them are arbitrary. However, at least one power receiving unit is provided in the isolated busbar path.
Further, when the busbar path is wider as it is farther from the power receiving unit, the width may change continuously,
It may be stepwise. The range of change to be given can be appropriately determined according to the power supply ratio and the like depending on the bus bar configuration, the number of power receiving units arranged, and the like. In general, the bus bar blocks light emission, and the increase in the occupied area leads to a decrease in the effective light emission area. Therefore, within 10 times based on the narrow width,
In particular, the rate of change is within 5 times.

In the present invention, the power receiving portions are arranged at least at two positions with respect to the bus bar.
The arrangement interval can be appropriately determined according to the bus bar configuration, the number of arrangements, and the like. It is preferable to arrange them at equal intervals rather than to evenly supply electric power, and it is preferable to arrange them on a path of one side or from a point of connection to an external power source or in a concentrated manner via a dividing portion. The power receiving unit may be formed as a lead electrode or the like in a state where it can be connected to an external power source,
It can be formed of an appropriate conductive material such as a metal foil.

The formation of the transparent electrode layer provided with the bus bar is
For example, a method of using a transparent conductive film formed by vapor-depositing a transparent conductivity-imparting agent such as indium or tin oxide, or applying a transparent conductive paint or the like obtained by adding the transparent conductivity-imparting agent to a binder. It can be performed by a method or the like. The transparent conductive paint or the like may be applied by an appropriate method such as a screen printing method, a casting method, a doctor blade method, or a roll coating method.

Examples of the binder include cyanoethyl cellulose, cyanoethyl saccharose, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, and fluorine. A vinylidene chloride-based copolymer or the like is preferably used. Further, a high molecular weight sol obtained by treating an organometallic compound such as tetraethoxysilane by a sol-gel method (JP-A-2-3388).
No. 8) can be preferably used. The binder can also be used for forming a light emitting layer and an insulating layer.

As the copolymer component with vinylidene fluoride in the above-mentioned vinylidene fluoride-based copolymer, tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropylene and the like 1
One kind or two or more kinds are used. For the preparation of the coating solution, an appropriate organic solvent such as cellosolve acetate, dimethylformamide, methyl ethyl ketone may be used.

The light emitting layer containing the fluorescent substance dispersed therein can be formed by, for example, a method of adding the fluorescent substance to a binder and coating the binder. As the phosphor, for example, zinc sulfide or cadmium zinc sulfide activated with copper, manganese, aluminum, silver, chlorine, boron, or the like, or an oxide such as rare earth activated yttrium oxide is generally used.
The average particle size of the phosphor is 10 μm or more, especially 15-40 μm
Is preferred. In addition, the volume occupancy of the phosphor in the light emitting layer is generally 30 to 80%. The fluorescent substance may be coated with a high dielectric substance or a water shielding material, and the coating layer may contain a fluorescent dye.

The EL light-emitting body of the present invention comprises a light-emitting layer 4 containing a phosphor dispersed therein as shown in FIG. 4, disposed between a transparent electrode layer 3 and a back electrode layer 6. The back electrode layer can be formed by, for example, a method of applying a conductive paint or a method of using an appropriate metal foil such as an aluminum foil.

In the present invention, the conventional method can be applied except that the transparent electrode layer provided with the bus bar having the above-mentioned power receiving portion is provided. Therefore, for example, attachment of an insulating layer, a cover layer, a water trapping layer, etc. and a forming means are optional. The means for forming the light emitting layer, the transparent electrode layer and the back electrode layer are also arbitrary.

The insulating layer provided as required can be formed by a method of applying an insulating resin, a method of laminating an insulating film, or the like. High dielectric constant fine particles such as barium titanate, lead titanate, zirconium titanate, titanium oxide, zinc sulfide, and silicon carbide may be blended in the insulating layer.

The above-mentioned cover layer is for surrounding the outside of the EL light-emitting body and protecting the inside thereof, and is generally provided in a usual practical mode. The thickness of the cover layer may be appropriately determined, but 50 to 500 μm is suitable from the viewpoint of thinning the EL light emitting body. An appropriate plastic film may be used for forming the cover layer.

The plastic film which can be preferably used for forming the cover layer has a small water absorption rate and a low water vapor transmission rate. Examples include polyvinylidene chloride and vinyl chloride.
Vinylidene chloride copolymer, polypropylene, high density polyethylene, tetrafluoroethylene / hexafluoroethylene copolymer, fluorinated ethylene / propylene copolymer, polyethylene terephthalate, ethylene / tetrafluoroethylene copolymer, polychlorotrifluoro Examples thereof include films made of ethylene or a copolymer thereof.

The water trapping layer, which is provided as necessary, is for preventing moisture from entering the light emitting layer, and is generally provided inside the cover layer. For its formation, a water-absorbent plastic which is insoluble in water but has a property of absorbing and capturing water and swelling is preferably used. Above all, it is preferable that the water absorption capacity is 5 times or more, and especially 10 times or more of its own weight.

Examples of the water-absorbent plastics include an ionizable group such as a carboxyl group, a sulfone group, a phosphoric acid group, a quaternary ammonium salt, an amino group, an imino group and a pyridinium group, or a salt thereof and / or a hydroxyl group, Examples thereof include natural or synthetic hydrophilic and water-insoluble polymers having a nonionic hydrophilic group such as an ether group, a chain or cyclic amide group, and a nitrile group.

Specific examples of the water-absorbent plastic include polyacrylamide, a blended polymer of polyacrylamide and polyolefin, a copolymer of acrylic acid or its salt and divinylbenzene, acrylonitrile, vinyl chloride and an ethylene monomer. Alkaline hydrolyzate of copolymer, Alkaline hydrolyzate of acrylonitrile / vinylidene chloride / ethylene monomer, Formaldehyde cross-linked acrylamide copolymer, Acid condensation of polyacrylic acid and polyvinyl alcohol Substance, epichlorohydrin cross-linked product of polyvinyl alcohol, formaldehyde cross-linked product of polymer obtained by hydrolyzing acrylonitrile polymer with alkali, phosphoric acid condensate of polyvinyl alcohol, 2-hydroxyethyl methacrylate and ethylene glycol dimetha Copolymer with relate, Copolymer with 2-methyl-5-vinylpyridine and N, N'-methylenebisacrylamide, with N, N'-dimethylaminoethyl methacrylate and N, N'-methylenebisacrylamide Copolymer, copolymer of N-vinyl-2-pyrrolidone and ethylene glycol dimethacrylate, cross-linked product of polyoxyethylene by irradiation of radiation, heat-condensation product of starch under acidic condition, saponification product of starch-acrylonitrile graft copolymer , A dry product of a copolymer of a vinyl ester and an ester unsaturated carboxylic acid or a derivative thereof, an isobutylene-maleic acid copolymer, and the like.

Examples of the method of forming the water-trapping layer include a method of applying a water-absorbent plastic solution and a method of laminating a film made of a water-absorbent plastic. The thickness of the water capturing layer is generally 20 to 300 μm, but is not limited to this.

Example 1 A resin paste containing silver powder was partially applied to one surface of a base substrate made of a polyester film having a thickness of 50 μm, and a width 1 having a 10 mm long cut portion in the central portion as shown in FIG.
After forming a bus bar consisting of a path 21 having a width of 2 mm, a path 22 having a width of 2 mm and a path 23 having a width of 4 mm, one lead electrode is attached to each corner of the path 21 and fluorinated with ITO dispersed therein. A transparent conductive paint consisting of a vinylidene copolymer cellosolve acetate solution is applied to form a transparent electrode layer (700 Ω / □) with a thickness of about 5 μm, and a phosphor made of zinc sulfide activated with copper and aluminum is applied. A dispersion of a vinylidene fluoride-based copolymer in a cellosolve acetate solution was applied to form a light emitting layer having a thickness of about 50 μm.

On the other hand, a conductive coating material containing silver powder is applied to one surface of a base substrate made of the same material as above to form a back electrode layer having a thickness of about 5 μm, and a lead electrode is attached to the base substrate. The layer-attached side is placed inside, and an adhesive layer (adhesive layer that also serves as an insulating layer) with a thickness of about 30 μm made of a cellosolve acetate solution of a vinylidene fluoride-based copolymer containing barium titanate is used to bond and bond the layers. Thickness 1 above and below the body
A polyvinylidene chloride film having a thickness of 00 μm was arranged, and the periphery of the film was adhered to form a hermetically sealed structure to obtain an EL luminescent material of 500 mm × 300 mm size.

The brightness of the EL light-emitting body was 100 nt (driving voltage: 100 V), and no uneven light emission was observed. On the other hand, after being left at room temperature (23 ° C.) for 100 hours under a driving condition of 100 V and 400 Hz, the heat generation and the luminance maintaining characteristics were examined, and as a result, the temperature distribution on the entire surface was about 3 on average.
The temperature was 0 ° C, and the difference between the high temperature part and the low temperature part was about 5 ° C. In addition, the luminance maintenance ratio (relative luminance when the initial luminance is 100, the same applies hereinafter) was 95%.

COMPARATIVE EXAMPLE As shown in FIG. 5, a bus bar having a width of 2 mm and having a substantially L shape was used.
An EL luminescent material was obtained in the same manner as in Example 1 except that one lead electrode was provided at the end portion, and the brightness and sustaining characteristics were examined. As a result, the brightness of the EL light-emitting body was 100 nt in the vicinity of the lead electrode, but was 60 nt in the vicinity of the corner where the bus bar was not present, and it became darker as it was further away from the bus bar, resulting in large variations in light emission. Further, regarding the maintenance characteristics, the temperature distribution on the entire surface is about 35 ° C on average, the difference between the high temperature part (lead electrode) and the low temperature part is about 50 ° C, and the temperature difference at both ends of the busbar is about 40 ° C. It was The luminance maintenance rate was 75%.

[0032]

According to the present invention, it is possible to obtain a large-area EL light-emitting body with less heat generation and uneven light emission. Further, it is possible to obtain an EL luminescent material which is less likely to warp due to heat generation and which is excellent in luminance and its maintainability, and in light emission life and uniformity of light emission. Moreover, by simply changing the bus bar configuration and the number of power receiving units arranged, it is possible to easily achieve a large area of the EL light emitting device by utilizing the conventional technique.

[Brief description of drawings]

FIG. 1 is an explanatory view illustrating a busbar configuration according to the present invention.

FIG. 2 is an explanatory view illustrating another busbar configuration according to the present invention.

FIG. 3 is an explanatory view illustrating still another bus bar configuration according to the present invention.

FIG. 4 is a sectional view of the embodiment.

FIG. 5 is an explanatory diagram of a conventional busbar configuration.

[Explanation of symbols]

1: Power receiving part 2: Busbar 21,22,23,24,25,26,27,28: Busbar route 3: Transparent electrode layer 4: Light emitting layer 6: Back electrode layer

Claims (3)

[Claims] 1. A light emitting layer containing a phosphor dispersed therein is provided between a transparent electrode layer provided with a bus bar and a back electrode layer, and the bus bar is provided around the transparent electrode layer. An EL light-emitting body having a power receiving portion arranged at two or more places with a space provided. 2. The EL light-emitting body according to claim 1, wherein the bus bar has a dividing portion at least at one position. 3. The E according to claim 1, wherein the bus bar is formed so that its width is changed stepwise or continuously, and the width becomes wider as the distance from the power receiving unit increases.
L luminous body.