JPS6237349Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a flexible electroluminescent lamp, and particularly to a sealing structure for an electroluminescent lamp that is sealed with resin through an adhesive.

In general, flexible electroluminescent lamps have a light-emitting element with a light-emitting layer in which phosphor powder is dispersed in a high dielectric material interposed between a pair of flat electrodes, at least one of which is transparent, and both sides of the light-emitting element are moisture-resistant. It has a structure in which a resin outer skin with good properties is placed and heat sealed between the resin outer skins around the light emitting element, and because it is sheet-like and flexible, it is used for display panels of various shapes and backlights of liquid crystal display devices. ing.

By the way, in flexible electroluminescent lamps that use a resin jacket in this way, moisture and water from the outside air permeate through the resin jacket during lighting and deteriorate the phosphor powder inside the luminescent layer. The outer skin uses a fluorine-based resin film with excellent moisture resistance. However, fluorine-based resin films generally have a high melting point;
In addition, due to poor adhesion, high sealing temperatures are required and the luminescent layer deteriorates, making it difficult to produce high-luminance products, and the sealing properties of the luminescent element become poor, making it impossible to achieve the desired moisture resistance. It has the following disadvantages. For this reason, it has been proposed to use a resin outer skin with a laminated structure in which a layered adhesive such as a polyethylene resin having a low melting point and excellent adhesiveness is applied to the sealing surface of a fluororesin film. The resin outer skin with such a laminated structure has a low melting point adhesive layer with good adhesion formed on the inner surface that seals the light emitting element, so the sealing temperature can be set low.
Therefore, moisture resistance can be obtained without causing brightness deterioration. However, even with this laminated resin outer skin that provides sealing properties and moisture resistance, during high-temperature thermal cycles and high-temperature/high-humidity tests, it peels off from the interface between the fluorine-based resin film and the adhesive layer at the outer edge of the seal. It was discovered that moisture entered from this area and deteriorated the phosphor. This solution involves a structure that does not expose the adhesive layer at the sealed outer end of the resin envelope, for example, the adhesive is selectively applied to the part of the resin film facing the light emitting element other than the planned sealed outer end. This is accomplished by performing sealing in two stages, the light-emitting element part and the peripheral sealing part, using a resin outer skin, but it is difficult to align the light-emitting element assembly,
This required two-step sealing, resulting in poor workability and was not a good solution.

The present invention was proposed in view of the above, and provides an electroluminescent lamp with good moisture resistance that does not cause peeling from the outer edge of the seal even in a high temperature and high humidity atmosphere without impairing workability or sealing performance. provide.

The electroluminescent lamp according to the present invention is characterized in that a light emitting element is sealed with a cylindrical resin film through an adhesive, and the adhesive is exposed on the sealed end surface located in the cylindrical part of the resin film. A sealing structure is obtained that does not cause peeling of the outer skin, and the problem of peeling of the outer skin is solved. In addition, by matching the dimensions of the cylindrical part of the resin film to the dimensions of the light emitting element inside, the sealing dimension around the element periphery can be made as small as possible to the thickness of the resin film, and the non-light emitting area can be reduced accordingly. Therefore, an electroluminescent lamp suitable for back lights of liquid crystal display devices, etc. can be obtained.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 1 and 2 show an electroluminescent lamp according to the present invention, in which a light emitting element 1 is sealed with a resin outer shell having a laminated structure with an adhesive layer formed on the inner surface.
That is, the light emitting element 1 has a normal structure in which a light emitter layer 5 is interposed between a pair of flat electrodes 3 and 4. For example, the upper transparent electrode 3 is made of indium oxide or the like on one side of a transparent insulating film 3a made of polyester or the like. A transparent conductive film 3b made of tin oxide or the like is uniformly coated, and the lower back electrode 4 is an Al foil, Al evaporated electrode, or printed electrode of Ag paste, and the intermediate light emitting layer 5
is a material in which zinc sulfide phosphor powder is dispersed in a high dielectric organic binder such as cyanoethyl cellulose.
and barium titanate particles dispersed in a high dielectric organic binder such as cyanoethyl cellulose are laminated in layers by screen printing or the like. And light emitting element 1
The entire structure is sealed with a resin outer cover 2 as described below, except for the external lead-out portions of the electrode leads 6 and 7 connected to the ends of both electrodes 3 and 4. That is, as shown in FIGS. 3 and 4, the resin outer skin 2 includes an adhesive layer 2b made of, for example, polyethylene resin, which has a low melting point and good adhesive properties, on the inner surface of a cylindrical, moisture-resistant film 2a, for example, a fluororesin film 2a. The cylindrical peripheral surface is completely covered with the moisture-resistant resin film 2a. The light emitting element 1 is then loaded into the cylindrical outer shell 2, and as shown in FIG. 5, it is pressed from both sides with a heat sealer 8 and bonded by thermocompression between the adhesive layers 2b on the inner surface of the outer shell 2. In an electroluminescent lamp sealed with such a cylindrical resin jacket 2, the peripheral surface of the resin jacket 2 is covered with a fluorine-based resin film 2a having good moisture resistance, and an adhesive layer is provided at the outer end of the seal. 2b is not exposed. Furthermore, although the adhesive layer 2b is exposed at the sealed outer end of the resin sheath 2 in the axial direction, the peripheral surface is integrally connected with the moisture-resistant resin 2a, and the sealed dimension a of this part is shown in Figure 2. If it is set to be long enough for the sealing width b as shown in Figure 2, it will not peel off like in the conventional case and can sufficiently withstand thermal cycles and high temperature and high humidity tests.

What is particularly noteworthy here is that if the inner diameter of the cylindrical resin outer skin 2 is set to approximately match the dimensions of the light emitting element 1, the sealing dimension l around the element periphery can be adjusted up to the thickness of the resin outer skin 2. The point is that it can be made as small as possible. In other words, in the case of the conventional light-emitting element 1 in which a resin outer cover is placed and sealed on each side separately, the sealing length is usually several mm or more due to the positioning of the element assembly and the reliability of the sealing strength. However, when used as a backlight for a liquid crystal device, the periphery of the display surface becomes dark. It is completely resolved. In the above embodiment, the resin outer skin is a cylindrical body with two integrated sides, but it is also possible to use a bag-like cylindrical body with three integrated sides, and the same effect can be obtained. is obtained.

As described above, the present invention provides an electroluminescent lamp in which a moisture-resistant resin outer cover with an adhesive layer formed on the inner surface is placed on both sides of a light-emitting element having a light-emitting layer between a pair of flat electrodes, and the outer cover is heat-sealed around the light-emitting element, and since the resin outer cover is formed into a continuous cylindrical shape on two or three sides, an electroluminescent lamp with excellent moisture resistance that does not peel off from the sealed outer end surface can be provided. In addition, excellent effects such as the ability to make the sealing dimensions as short as possible and being suitable for liquid crystal display devices can be obtained. In the above embodiment, the resin outer cover is a laminated resin film with an adhesive layer formed on the inner surface, but this is not necessarily required, and the same effect can be obtained, for example, by coating an adhesive on the surface of the light-emitting element.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the electroluminescent lamp according to the present invention, Fig. 2 is a front view taken along the - line in Fig. 1, Fig. 3 is a perspective view of the resin jacket used in Fig. 2, and Fig. 4 is a cross-sectional view of the electroluminescent lamp according to the present invention. 3
5 is a sectional view taken along the - line in the figure, and FIG. 5 is a sectional view of the manufacturing process shown in FIG. 1. 1...Light emitting element, 2a...Resin film, 2b
...Adhesive material (adhesive material layer).

Claims (1)

[Scope of utility model registration request] An electroluminescent lamp characterized in that a light emitting element is sealed with a cylindrical resin film via an adhesive.