JPH0521159A - El element - Google Patents

Abstract

PURPOSE:To reduce production cost by preventing a deterioration in the light emitting layer of an EL element and by thinning the layer. CONSTITUTION:A transparent electrode layer 2 is provided on the rear of a transparent base film layer 1. A light emitting layer 3 having an area smaller than that of the transparent electrode layer 2 is provided on the rear of the transparent electrode layer 2. An insulating layer 4 is provided on the rear of the light emitting layer 3 to cover the surroundings. The insulating layer 4 comprises barium titanate having high electric constant and polyamide serving as a hygroscopic substance. The insulating layer 4 plays the role of a water capture layer to prevent moisture from being entered into the light emitting layer 3, preventing a deterioration in the light emitting layer 3. The layered product is sealed by a moisture-proof film 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EL device.

[0002]

2. Description of the Related Art In a conventional electroluminescence device (hereinafter referred to as "EL device"), a transparent electrode made of ITO is formed on a transparent base film, and zinc sulfide is coated with an activator such as copper or chlorine. A luminescent layer composed of the luminescent particles contained therein and an organic binder (such as cyanoethylated cellulose) is formed. A back electrode made of an aluminum layer or the like is formed on the other surface of the light emitting layer with an insulating layer such as barium titanate interposed therebetween. Since the light emitting layer deteriorates even if a small amount of water enters, a water trapping layer such as a polyamide resin is provided outside the back electrode and the transparent base film in order to prevent water from entering the light emitting layer. The outer sides of the water trapping layers on both sides are sandwiched by a moisture-proof package film containing poly (trifluorochloroethylene) as a main component, through which gaseous water in the air is difficult to pass, and the outer peripheral portion is sealed by thermocompression bonding.

[0003]

As in the above-mentioned conventional example,
In the case where the water trapping layer is provided outside the transparent base film and the back electrode, the light emitting layer is not surrounded by the water trapping layer, so that there is a problem that a complete moistureproof effect cannot be expected. is there. In addition, since the water trapping layer is formed in two layers, the thickness of the EL element is correspondingly increased, and the water trapping layer, which is time-consuming to form, must be formed twice, which increases the manufacturing cost. Is becoming

Therefore, an object of the present invention is to prevent deterioration of the light emitting layer by completely preventing moisture from entering the light emitting layer, and to reduce the thickness of the EL element by omitting the formation of the water trapping layer. And it is to reduce the manufacturing cost.

[0005]

Since the back surface and the periphery of the light emitting layer are covered with the insulating layer containing a hygroscopic substance, moisture cannot penetrate into the light emitting layer. Further, since the insulating layer also serves as the water trapping layer, it is not necessary to form one water trapping layer which should be formed in two layers, and the thickness of the EL element is reduced.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, the basic structure of the present invention is that a transparent electrode layer 2 made of ITO is laminated on the back surface (upper side of FIG. 1) of a transparent base film layer 1 as in the conventional example. ..

On the back surface of the transparent electrode layer 2, a light emitting layer 3 containing zinc sulfide as a main component is provided in an area smaller than this. An insulating layer 4 is formed so as to cover the back surface of the light emitting layer 3 and the periphery thereof. The light emitting layer 3 is completely surrounded by the insulating layer 4 and the transparent electrode layer 2.

The insulating layer 4 is formed by adding barium titanate having a high dielectric constant, a binder made of a high dielectric polymer and a solvent in a printable ratio, and further adding a polyamide as a hygroscopic substance. .. As the conditions for the polyamide, those having a molecular weight of 2000 or less are desirable in view of the balance between insolubility in a solvent and compatibility with a binder. Further, the amount of polyamide added is preferably 5 to 30 wt% in consideration of the balance between the water capturing effect and the high dielectric property.

A back electrode 5 made of an aluminum layer having a thickness of 0.1 mm is provided on the back surface of the insulating layer 4. On the front surface (lower side in FIG. 1) of the transparent base film layer 1, a water capturing layer 6 made of polyamide resin is provided.

The back electrode 5 and the water trapping layer 6 are sandwiched by moisture-proof package films 7 and 7 made of poly (trifluorochloroethylene), and the periphery of the laminate such as the light emitting layer is bonded by thermocompression bonding. It is sealed.

As another embodiment, in order to enhance protection of the light emitting layer, an insulating layer containing no hygroscopic substance is provided between the light emitting layer and the insulating layer containing a hygroscopic substance to form two layers. Good. Since the insulating layer has a small thickness and can be easily formed by screen printing, the moisture-proof effect can be improved with almost no disadvantage in terms of thickness and manufacturing cost.

[0012]

As described above, according to the present invention, since the light emitting layer which is weak against moisture is covered with the insulating layer containing the hygroscopic substance, deterioration due to moisture can be prevented. Further, since the insulating layer also serves as a water trapping layer, it is possible to omit the time-consuming formation of the water trapping layer, which can reduce the manufacturing cost, and further reduce the water trapping layer to reduce the thickness of the EL element. There is an effect that can be done.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 1 Transparent Base Film Layer 2 Transparent Electrode Layer 3 Light Emitting Layer 4 Insulating Layer 5 Back Electrode

Claims (1)

Claim: What is claimed is: 1. A transparent electrode layer provided on the back surface of a transparent base film layer, and a transparent electrode layer provided on the back surface of the transparent electrode layer and having an area smaller than that of the transparent electrode layer. A light emitting layer, an insulating layer containing a hygroscopic substance and provided on the back surface of the light emitting layer and covering the periphery of the light emitting layer, and a back electrode provided on the back surface of the insulating layer. An EL element characterized by being provided.