JPH05166582A - Manufacture of el element - Google Patents

Abstract

PURPOSE:To reduce the rate at which brightness of an electroluminescent element is lowered at early stages of lighting and to prolong the life of the element by forming a conductive layer, a dielectric layer and a light-emitting layer on a base film by means of screen printing in sequence, and setting the water content of this stack to no more than 0.2%. CONSTITUTION:Conductive ink having silver powders dispersed therein is screen printed on a base of a polyester film 4 or a nylon film 6 and is dried to form a conductive layer 3. Ink having dielectric substance such as barium titanate dispersed therein is similarly printed thereon and is dried to form a dielectric layer 2 and further ink in which emitter particles composed chiefly of zinc sulfate are dispersed is similarly printed thereon and is dried to form a light- emitting layer 1 to fabricate a stack. When the water content of the stack is not less than 0.2%, the stack is dried by heat to reduce the water content and then a polyester film 5 equipped with a transparent electrode is stuck onto the layer 1 and a nylon film 6 and a fluorine film 7 are stuck to the upper and lower surfaces of the stack, respectively, to obtain a product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device such as a personal computer and an operation panel, and a backlight of a key input portion such as a mobile phone and a remote controller, or an instrument panel, an emblem, an identification light and an emergency light for automobiles. The present invention relates to a method of manufacturing an EL element which is used as a lamp for applying an electric field to emit light.

[0002]

2. Description of the Related Art In a conventional EL element in which a back electrode is formed of a conductive ink, a light emitting layer is first formed on a film with a transparent electrode, and another dielectric layer and a conductive layer are sequentially laminated thereon. I am producing.

An EL whose back electrode is made of aluminum foil
Elements are also known.

[0004]

Among the prior arts, the first one mentioned above has a structure in which another layer is laminated on the light emitting layer, so that 0.3% or more of water remains in the light emitting layer. Therefore, there is a drawback in that the brightness is significantly lowered in the initial stage of lighting.

Further, the aluminum foil used as the back electrode has a structure in which the light emitting layer is formed at the end so that moisture can be easily removed. Even in this case, however, the luminance starts to decrease from the beginning of lighting and the life is short. It has drawbacks.

[0006]

Therefore, according to the present invention, by finally forming a light emitting layer so as to easily remove moisture, and by using a conductive ink as a back electrode,
We have made it possible to manufacture EL elements that have a longer life than conventional aluminum foil.

According to the manufacturing method of the present invention, a conductive layer is formed by screen-printing with a conductive ink on a base film, and a dielectric layer is similarly screen-printed with an ink in which a dielectric substance is dispersed on the conductive layer. To form a luminescent layer by screen printing with an ink in which luminescent particles are dispersed on the dielectric layer to form a luminescent layer, and then, if necessary, the water content of the laminated body is 0. Drying to below 2%.

[0008]

EXAMPLES Next, examples of the present invention will be described.

A conductive ink in which silver powder is dispersed is screen-printed on the base of the polyester film 4 or nylon film 6 and heat-dried at 100 ° C. for 1 hour to form a conductive layer 3, and titanium is formed on the conductive layer 3. Printing is similarly performed with an ink in which a dielectric substance such as barium acid powder is dispersed, and heat drying is performed at 100 ° C. for 1 hour to form a dielectric layer, and then light emission using zinc sulfide as a base material is formed on the dielectric layer. Printing is similarly performed with an ink in which body particles are dispersed, and heat drying is performed at 100 ° C. for 1 hour to form a light emitting layer, thereby producing a laminate.

It was confirmed that the water content of the produced laminate was 0.2% or less, and if it was more than 0.2%, it was heat dried to 0.2% and the polyester film with a transparent electrode was formed on the light emitting layer 1. 5 is hot-pressed or hot-pressed to bond them together, and finally, if the upper and lower surfaces of the polyester film with transparent electrode 5 on the upper surface of the laminated body are the polyester film 4, a nylon film 6 is arranged below the polyester film 4. The fluorine film 7 is arranged and bonded by a heat press or a heat pressure roll to obtain a product.

When using this EL element, the conductive layer 3
An alternating voltage is applied to the transparent electrode-attached polyester film 5 to cause the light emitting layer 1 to emit light.

[0012]

According to the present invention, the light emitting layer is finally formed,
Since the back electrode is screen-printed with the conductive ink, the water content of the laminate can be kept to 0.2% or less due to the structure in which the water content of the laminate can be easily removed, and there is no significant decrease in the brightness at the initial stage of lighting. Therefore, it is possible to reduce the deterioration gradually, and it becomes possible to manufacture an EL element having a long life.

A graph of FIG. 2 shows a comparison of this decrease in brightness with the above-mentioned conventional technique. In the experiment, except for nylon for trapping moisture and fluorine film for preventing moisture,
The applied voltage was 100 V AC and 400 Hz under open air. A solid line A is a product according to the present invention, and a dotted line B is a conventional product in which a dielectric layer and a conductive layer are formed on the light emitting layer and has a water content of 0.4%. And the one-dot chain line C is
The back electrode was made of aluminum foil with a water content of 0.2%.

As can be seen from FIG. 2, the initial luminance decrease of the line B conventional product is large, and the initial luminance reduction of the line C conventional product is slower than that of the line B.
The amount of decrease is large and the life is short.

[Brief description of drawings]

FIG. 1 is a structural diagram of an EL element.

FIG. 2 is a comparative graph of brightness reduction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting layer 2 Dielectric layer 3 Conductive layer 4 Polyester film 5 Polyester film with transparent electrode 6 Nylon film 7 Fluorine film A Present product B, C Conventional product

Claims (1)

[Claims] 1. A conductive layer is formed by screen printing with a conductive ink in which a conductive substance is dispersed on a base film,
A laminated body in which a dielectric material is dispersed on the conductive layer to print to form a dielectric layer, and the luminous layer is further dispersed on the dielectric layer to print to form a luminescent layer. And a method for manufacturing an EL element, wherein the laminated body is dried until the water content is 0.2% or less.