JPH03127487A - Dispersion type el panel - Google Patents

Abstract

PURPOSE:To realize a low cost and a long service life by including an infusible silicone resin powder with a specific particle diameter in a luminous layer. CONSTITUTION:Inside a luminous layer 23, a ball-form infusible type silicone resin powder with the mean particle diameter in the scope 0.5mum to 10mum, preferably 1 to 5mum, is included in the scope 1.0 to 20.0wt.%. By including the silicone resin powder in the luminous layer in such a way, the water permea bility can be improved without hurting the luminous property, the using amount of an outer film of a high cost can be reduced, and a dispersion type EL panel of a low cost and a long service life can be obtained. In this case, the infusible type silicone resin powder is a silicone resin powder furnishing a three- dimensional mesh composition by the siloxane combination, and as an organic radical to combine with silicon, an aliphatic radical such as methyl radical and ethyl radical, an aromatic hydrocarbon radical such as methyl phenylene radical, an unsaturated hydrocarbon radical including a vinyl radical, and the like are available. Especially, the methyl radical is preferable.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention is directed to a long-life dispersion light source used for illumination light sources, display elements, auxiliary light sources as backlights of liquid crystal display devices, etc. The present invention relates to EL panels, and particularly to improvements in their light-emitting layers.

(Conventional technology) An example of a conventional distributed type El panel is shown in FIG.

As shown in the figure, an organic dielectric material 2a such as cyanoethyl pullulan or cyanoethylpoval is placed on a back electrode 1 made of aluminum foil or the like with an alumite layer formed on the surface.
A reflective insulating layer 2 made of a mixture of white inorganic dielectric powder 2b such as barium titanate, and a luminescent layer 3 made of a dispersion of zinc sulfide phosphor particles 3b and an organic fluorescent pigment 3c in an organic dielectric 3a are laminated. It is formed.

On the other hand, on the opposite side of the reflective insulating film 2 of the light-emitting layer 3, a transparent conductive film 4 made of a polymer film with a transparent electrode formed on the side in contact with the light-emitting layer 3 is laminated. A water-trapping film 5 made of nylon 6 or the like is placed on the outer surface of the transparent conductive film 4 and the back electrode l, respectively.
A moisture-proof film 6 containing trifluorochloroethylene as a main component is laminated.

In such a dispersion type EL panel, PET, which has relatively excellent moisture permeability barrier properties among various polymer films, is used as the polymer film for the support of the transparent conductive film. 3b deteriorates significantly due to moisture absorption, significantly impairing the luminescent properties. Therefore, the moisture-proof film 6 is made of various polymer films, such as a polymer film whose main component is trifluorochloroethylene, which is the least permeable to moisture, and the water-capturing film 5 is provided inside the film. It has a double moisture-proof structure that traps trace amounts of moisture passing through the polymer film 4 before reaching the light emitting layer 3.

However, by adopting such a double moisture-proof structure, the cost related to this double moisture-proof structure is reduced compared to the distributed EL.
It accounted for about half of the total cost of the entire panel, was an obstacle to lower prices, and was a cause of hindering wider adoption.

For this reason, there has been a demand for a dispersed EL spring that has improved moisture resistance without causing the above-mentioned high price.

(Problem to be solved by the invention) As described above, in the moisture-proof structure that relies on the conventional outer skin film,
Not only does this result in higher costs, but the inside of the light emitting layer does not inherently have a structure with improved moisture resistance, so in a distributed EL panel using this, deterioration due to moisture absorption into the light emitting layer can be completely prevented. There was a problem that I couldn't do it.

The present invention was made in order to solve the above-mentioned conventional problems, and aims to significantly improve the moisture permeability inside the light emitting layer and provide a low-cost, long-life dispersion type EL panel. be.

[Structure of the Invention] (Means for Solving the Problems) The dispersion type EL panel of the present invention consists of a back electrode on which a reflective insulating layer is formed on the surface, and a transparent conductive film on which a transparent conductive thin film is formed on at least the surface. In a dispersed EL panel constructed by arranging transparent electrodes facing each other and sandwiching a light-emitting layer between the back electrode and the transparent electrode, the light-emitting layer is provided with spherical particles having an average particle size in the range of 0.5 μm to 10 μm. It is characterized by containing non-melting silicone resin powder in a range of 1.0 to 20.0% by weight.

The non-melting silicone resin powder used in the present invention is a silicone resin powder that has a three-dimensional network structure due to siloxane bonds, and organic groups that bond to silicon include methyl groups, ethyl groups, etc., and aliphatic hydrocarbons. group, an aromatic hydrocarbon group such as a phenylene group, and an unsaturated hydrocarbon group having a vinyl group. Among them, a methyl group is preferable. In addition, various modified silicone resin powders can also be used as long as they do not impair the hydrophobicity of the silicone resin powder.

Silicone resins are generally available as silicone varnish made by dissolving the initial condensate in a suitable solvent.
The silicone resin used in the present invention contains a solvent and has a good average particle size in the range of 0.5 μm to 0 μm, preferably 1 μm.
It is a powder in the range of ~5 μm, and is a substantially insoluble and infusible substance that has been thermoset.

Further, the shape of the silicone resin powder used in the present invention is spherical, particularly, the sphericity f expressed by the following formula (1) is 0.
8 or more is preferred.

f= π D old construction ・・・・・・
(1) In the formula, A is the cross-sectional area of the polymer powder, D+ux is the cross-sectional area of the polymer powder, and Dmax is the longest diameter of the cross-section of the polymer powder. Sphericity does not directly contribute to improving the water permeability of the light-emitting layer, but it particularly affects the slipperiness when laminating the light-emitting layer and the transparent conductive film and the surface properties of the EL element.

The average particle size of silicone resin powder is 0.5 μm to 10 μm
1, particularly preferably in the range of 1 μm to 5 μm.

When the average particle size exceeds 10 μm, the surface flatness becomes insufficient and the transparency of the light emitting layer deteriorates. Also,
When the average particle size is less than 0.5 μm, it is difficult to obtain monodisperse particles.

The amount of silicone resin powder added in the present invention needs to be 1.0 to 20.0% by weight, preferably 3 to 18% by weight, based on the organic dielectric material. Addition amount is 1゜0
If it is less than % by weight, no improvement in the water permeability of the luminescent layer can be expected;
On the other hand, if it exceeds 20% by weight, the surface flatness will decrease and the transparency of the film will deteriorate, which is not preferable.

(Function) In the dispersion type EL spring of the present invention, spherical non-melting silicone resin powder with an average particle size in the range of 0.5 μm to 10 μm is contained in the range of 1.0 to 20.0% by weight in the light emitting layer. Therefore, water permeability can be improved without impairing the luminescent properties, the amount of expensive outer film used can be reduced, and a low-cost, long-life distributed EL panel can be obtained.

(Example) Hereinafter, an example of the distributed EL panel of the present invention will be described with reference to the drawings.

As shown in FIG. 1(a), a binder solution containing cyanoethyl pullulan and cyanoethylpoval dissolved in dimethylformamide (hereinafter referred to as DMF) is placed on the back electrode 21 made of aluminum foil with an alumite layer formed on the surface. After printing a reflective insulating layer paste in which barium titanate powder with an average particle size of 1 μm was dispersed in this binder solution by screen printing, it was dried in an N2 atmosphere at about 120°C for 2 hours to remove DMF, and then 30
A reflective insulating layer 22 of μm thickness was obtained.

Next, on this reflective insulating layer 22, a layer with a flat grain size of 1°2 μm is applied.
Zinc sulfide phosphor powder 23b is added to a binder solution to which 10% by weight of non-melting silicone resin powder 23a (for example Tospearl 120: manufactured by Toshiba Silicone Co., Ltd.) with a sphericity of 0.87 to 0.93 is added to ~1.3 μm1. and organic fluorescent pigment 23
A light emitting layer paste in which c was dispersed was printed by screen printing, and dried in an N2 atmosphere at about 120 C for 2 hours to remove DMF, and a light emitting layer R23 of about 30 μm was obtained.

On the other hand, as shown in FIG. 1(b), on the transparent electrode of the transparent conductive film 24, an Ag base is printed by screen printing, and then a thermally cured current collector electrode 25 is formed. An extraction electrode 26 made of phosphor bronze or the like is temporarily fixed at a predetermined position of the electrode 25 and the back electrode 21 with PET tape or the like.

After this, using a thermal laminator, the roll surface temperature was 150C.
~170C, linear pressure 5~10 kg/cm, feed rate 1
The transparent electrode and the light emitting layer 23 are bonded together under conditions of 0 to 30 cm/min.

Then, a water-catching film 27 made of nylon 6 and a moisture-proof film 28 made of trifluorochloroethylene in combinations shown in Table 1 below were laminated together.

The thus obtained dispersed EL panel was heated to 95% at 40°C.
A life test was conducted by applying 110V and 500Hz under high temperature and high humidity. The results are shown in FIG. Note that the horizontal axis in the figure is expressed in logarithms.

As shown in the figure, the distributed EL panel of the present invention is
As a result of suppressing the water permeability of the light-emitting layer 23, deterioration due to moisture absorption is suppressed, resulting in a long life, and even if the thickness of the trifluorochloride ethylene film, which accounts for the largest proportion of the cost, is halved, it is still as good as the conventional product. It was confirmed that the same lifespan could be obtained and the price could be lowered.

Further, in the distributed EL panel of the present invention, some improvement in brightness was observed. This is thought to be due to the light scattering effect of the non-melting silicone resin powder added to the light emitting layer.

[Effects of the Invention] As explained above, the distributed EL panel of the present invention has the following effects:
Since non-melting silicone resin powder is added to the light-emitting layer, water permeability is suppressed, extending life and reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating the structure of a dispersion type EL panel according to an embodiment of the present invention, FIG. The figure is a schematic diagram illustrating the structure of a conventional distributed type El panel. 2 (...... Back electrode 24...
......Transparent conductive film 22...
...Reflective insulating layer 25 ...... Current collector electrode 23 ...... Light emitting layer 26 ...... Extracting electrode 23a...
...Non-melting silicone resin powder 27...
...Water-capturing film 23b... Fluorescent body 28... Moisture-proof film 23c...
...Organic fluorescent pigment

Claims (1)

[Claims] A back electrode with a reflective insulating layer formed on its surface and a transparent electrode made of a transparent conductive film with at least a transparent conductive thin film formed on its surface are arranged facing each other, and a light emitting layer is sandwiched between the back electrode and the transparent electrode. In the dispersion type EL panel, the light emitting layer contains particles with an average particle size of 0.5 μm to 10 μm.
A dispersion type EL panel characterized in that it contains spherical non-melting silicone resin powder in the μm range.