JPH0422097A - Dispersion type electroluminescent lamp and its manufacture - Google Patents

Abstract

PURPOSE:To retain conductivity with a cracking part covered with an organic binder even if the crack occurs in an ITO evaporation layer by making a transference electrode have two layers of a layer in which ITO is evaporated, and a layer on which conductive oxide powder, selected from ITO, In2O3, or SnO2, is applied together with the organic binder. CONSTITUTION:An ITO layer 11 is evaporated in the resin film 4 of polyethylene, etc., as a transference electrode on a transference electrode side. Then a structure is made which has an organic binder and an ITO powder layer 12 on which ITO powder is applied, and in which a luminous element, in which a phosphor layer 3 and the ITO powder layer 12 are facingly pressed, is closedly sealed with a moisture-proof film 5. By the way, substance such as In2O3 and SnO2, similarly having good conductivity, can be used as conductive oxide powder applied on the transference electrode side besides ITO. Consequently, even if a crack occurs in the ITO evaporation layer 11, a large screen is available because the crack is compensated with the conductive oxide powder layer 12 having flexibility to retain conductivity.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a distributed electroluminescent lamp (hereinafter referred to as a distributed EL).
and its manufacturing method.

[Prior art and its problems] Generally, as shown in FIG. 2, in a distributed EL, a back electrode 1,
A transparent electrode layer (ITO vapor deposition layer) 1 in which a reflective insulation N2 and a phosphor layer 3 are laminated in order, and ITO (indium tin oxide) is separately vapor-deposited on a transparent resin film 4 such as polyester.
The device has a structure in which a light-emitting element 1 is pressed against a phosphor layer 3 and hermetically sealed with a moisture-proof film 6.

However, if the above-mentioned distributed EL is made larger, JP-A-2-79
As described in Japanese Patent Application No. 392, there is a fatal problem in which cracks form in the transparent electrode layer 1, making it impossible to emit light.

In order to solve this problem, in JP-A-2-79392, ITO was added on the phosphor N3 in addition to the transparent electrode layer.
A technique has been disclosed in which a powder is applied via a binder to form an ITO layer, and then the ITO layer is pressed against the transparent electrode N11 to compensate for generated cracks with the ITO powder layer.

However, this technique of forming an ITO powder layer on the phosphor layer 3 side requires a large amount of ITO powder to obtain a uniform surface because the phosphor side has a rough surface. Using a large amount of ITO powder, which is a non-luminescent substance, results in a reduction in the brightness of the dispersed EL. Further, since the phosphor layer 3 of the dispersed EL is very sensitive to moisture, it usually takes more than ten hours to completely dry the phosphor layer 3 formed by coating the phosphor. Furthermore, if a T'0 powder layer is formed and dried, more time is required, resulting in a problem that the manufacturing process and time become longer.

[Problems to be solved by the invention] The present invention has been made in view of the above circumstances,
The object of the present invention is to provide a large-area dispersed EL that is easy to work with and uses a small amount of conductive oxide powder, and a method for manufacturing the same.

[Means for Solving the Problems] In the dispersion type EL of the present invention, the transparent electrode layer has I as the first layer.
A layer in which TO is vapor-deposited and a second layer of ITO1In20B
Alternatively, the present invention is characterized by comprising two layers: a layer in which at least one kind of conductive oxide powder selected from SnO2 is coated together with an organic binder.

[Example] Hereinafter, a manufacturing method for obtaining a dispersed EL according to the present invention will be explained in detail with reference to an example.

FIG. 1 is a cross-sectional view showing the structure of the distributed EL according to the present invention. As in the conventional case, the back electrode is made of aluminum foil or the like on the back electrode side.
, a reflective insulating layer 2 such as barium titanate, and a phosphor N3 such as copper-activated zinc sulfide are laminated in this order. On the other hand, on the transparent electrode side, 170 layers 11 were deposited on a resin film 4 made of polyethylene or the like as a transparent electrode in the same manner as before, and then an organic binder and ITO powder, which is a feature of the present invention, were applied.
It has a structure in which a light emitting element is provided with a To powder layer 12, and finally a light emitting element, which is crimped with a phosphor layer 3 and an ITO powder N12 facing each other, is hermetically sealed with a moisture-proof film 5.

In the method for manufacturing a distributed EL according to the present invention, the back electrode side can be formed by a normal method, so the explanation thereof will be omitted. On the other hand, the transparent electrode side can be formed by the following method.

First, ITo is deposited on a transparent resin film 4 made of polyester or the like. Next, an ITO powder slurry (hereinafter referred to as slurry) is prepared in order to form an ITO powder layer 12 thereon. The slurry consists of ITO powder, 40% by volume of PVA as an organic binder based on the powder, and methyl ethyl ketone as a solvent, and the viscosity of the slurry is 50 CPS (
centiboise) to 300 CPS and thoroughly mixed. As the organic binder, binders such as PVA, acrylic resin, epoxy resin, and cyanoethyl cellulose can be used, and the amount added is usually 1 to 50% relative to the ITO powder in order to impart conductivity to the ITO powder layer 12. % by volume, preferably 2
Add 0 to 40% by volume. Further, as a solvent, methyl ethyl ketone, dimethyl formamide, acetone, etc. can be used.

Next, this slurry was applied to the ITO-deposited transparent resin film 4 by a screen printing method, and then dried at 50° C. for 2 hours to volatilize the solvent in the slurry.
Dry again in a vacuum dryer for 8 hours.

The transparent resin film 4 in which the 170 layer 11 and the ITO powder layer 12 were formed in the above manner was placed opposite to the phosphor layer 3 on the back electrode side, and primary pressure bonding was performed to create a light emitting element. The dispersion type EL of the present invention is produced by secondary pressure bonding of the light emitting element from above and below with a moisture-proof film.
can be obtained.

In addition to ITO, the conductive oxide powder applied to the transparent electrode includes Ir+203. SnO2
Substances such as the following can be used. The average particle size of these oxide powders is 10 μ or less, preferably 0.1 layer or more.
It is preferable that the coating thickness is 015μ or more and 10μ or less. This is because In2O3 and SnO2 powders have a white or pale yellow body color, and ITO powders have a yellow-green body color. If they are applied together with a binder to a thickness of 10 μm or less, the applied layer will be almost transparent, but if it is more than that, body color will appear in the applied layer, causing a decrease in brightness. On the other hand, if the coating thickness is less than 0.5μ, IT
If the O evaporated layer is cracked, the oxide powder layer is also cracked, resulting in poor conductivity. Moreover, if the particle size is 10 μm or more, the particles will be reflected on the light emitting surface, resulting in a decrease in brightness.

[Function] Even if cracks occur in the ITO vapor deposition layer and electrical conductivity is interrupted, the organic binder has flexibility in the conductive oxide powder layer such as ITO on the transparent electrode side and covers the cracks. By doing so, conductivity can be maintained.

[Effects of the Invention] The manufacturing method of the present invention has a flat r
It has the advantage of requiring less powder to be applied to the RO vapor deposited layer.

Fig. 3 shows the state of contact between the ITO powder layer 12 and the phosphor layer 3 of the dispersion type EL of the present invention and Fig. 4 of the conventional dispersion type EL having the ITO powder layer 12 on the side of the phosphor layer 3. An enlarged schematic cross-sectional view is shown. The light emission of the dispersed EL phosphor of the present invention is caused by the M of the JTO powder passing through the ITO powder layer.
Since the thickness is almost constant and the amount is small, there is less reduction in brightness due to interference with luminescence of the ITO powder color and less uneven brightness than in the conventional case.

In addition, in the conventional manufacturing method, a process of drying the phosphor layer 3 and a process of drying the ITO powder N12 must be performed, resulting in a very long manufacturing time. On the other hand, according to the manufacturing method of the present invention, the above-mentioned two steps can be performed in parallel, so that the time delay can be shortened.

In this way, the dispersed EL of the present invention can maintain conductivity even if cracks occur in the ITO deposited layer 11, as the flexible conductive oxide powder N12 compensates for the cracks. Therefore, a large screen is possible.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of the distributed EL of the present invention, and FIG.
The figure is a cross-sectional view showing the structure of a conventional distributed EL, FIG. 3 is an enlarged schematic cross-sectional view of the distributed EL of the present invention, and FIG. 4 is a conventional I
FIG. 2 is an enlarged schematic cross-sectional view of a dispersed EL having a TO powder layer. 1. Back electrode, 2. Reflective insulating layer, 3. Phosphor layer,
4...Resin film, 5...Moisture-proof film 11...IT
O vapor deposition layer, 12...I T'O powder layer.

Claims (2)

[Claims] (1) In a distributed electroluminescent lamp in which a phosphor layer and a transparent electrode layer are opposed to each other, the transparent electrode layer has a layer in which ITO is vapor-deposited as a first layer, and ITO and In_2O_3 as a second layer. or SnO_2
A distributed electroluminescent lamp comprising two layers: a layer coated with at least one kind of conductive oxide powder and an organic binder. (2) In the method for manufacturing a distributed electroluminescent lamp in which a phosphor layer and a transparent electrode layer are opposed to each other, the transparent electrode layer is formed by depositing ITO on the first layer, and then depositing ITO on the second layer.
A method for manufacturing a distributed electroluminescent lamp, characterized in that the layer is formed by applying a slurry of a mixture of at least one type of conductive oxide powder selected from ITO, In_2O_3, or SnO_2 and an organic binder. .