JPS6127094A - Electroluminescent light emitting element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an electroluminescence light emitting device (hereinafter referred to as EL).
D), and particularly relates to the moisture-proof structure of ELDs.

[Background of the invention]

The phenomenon of light emission caused by applying a voltage to a light emitting layer made of ZnS or the like in which manganese or the like is diffused has been known as electroluminescence.

FIG. 1 is a cross-sectional view of a conventional 7-lexiple dispersion type ELD.

In FIG. 1, the lower electrode 1 is formed of, for example, metal powder such as silver dispersed in an organic polymer or inorganic binder, or a thin metal film of aluminum, copper, or the like.

Luminescent M2 is made by dispersing a phosphor powder in which ZnS is doped with an activator such as copper or manganese and an inert agent such as chlorine into an organic polymer binder. There are also those using elements, -valent metals, transition metals, etc.

The transparent electrode 3 is formed of a thin film of metal oxide such as InzOt or Snow, a thin film of gold or palladium, or a thin film of metal such as aluminum or copper in which small mesh-like holes are formed.

The upper part of the transparent electrode 3 is covered with a transparent water-absorbing layer 4 made of a polymer film such as polyamide resin with good light transmittance and high water absorption, and the lower part of the lower electrode 1 is covered with CaO, CaSα, etc.
The lower electrode 1 can be coated with a paste containing desiccant powder and organic polymer dissolved in a solvent, or by using an adhesive.
The desiccant powder described above is attached to the film, or a moisture absorbing material is similarly applied to a polymer film such as a polyamide resin, and these are formed into a moisture-proof film A consisting of a heat-melting film 7 and a water-polishing film 8 such as a fluororesin. (laminate film) 9, and the moisture-proof films 9 and 9 were heat-sealed or sealed with an adhesive or the like 10 to form a moisture-proof structure.

However, the surfaces of the moisture-proof films 9 and 90 and the seal portion 10
Also, since a small amount of moisture enters from the sealing part 10 from a lead wire extraction part (not shown), etc., the moisture-proofing effect is not sufficient.

In addition, the water-absorbing layer ((The polymer film used, such as polyamide resin, has a low dehydration start temperature and easily releases moisture when the ambient temperature rises, so the internal humidity tends to increase.

For this reason, a desiccant such as CaO or CaSO4, which is difficult to release even at high temperatures, is used at the bottom of the lower electrode to absorb this moisture. It is not possible to absorb all the moisture released from the layer 4, and the excess moisture enters the light-emitting layer 2, which causes the ELD to emit light in the presence of moisture, causing the ELD to emit light. It had a drawback that it had a negative effect on the luminescence life of the device.

[Purpose of the invention]

The present invention aims to eliminate such conventional drawbacks,
The purpose of this is to reduce the amount of moisture in the ELD as much as possible, and prevent moisture from entering the light emitting layer, thereby extending the life of the light emitting device.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention provides an extending portion in at least one of the transparent water-catching layer and the water-catching layer, and brings the two water-catching layers into close contact with each other.

[Embodiments of the invention]

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

2 to 5 are cross-sectional views of the ELD according to the present invention.

In FIGS. 2 to 5, numerals 1 to 10 indicate the same parts as the conventional ones.

11 is an extension of the transparent water-trapping layer 4, and 12 is an extension of the water-trapping layer *6.

In such a structure, the difference between the conventional ELD shown in FIG. 1 and the EL'D of the present invention shown in FIGS. 6 was isolated and the transparent water-catching layer 4 and the water-catching layer 6 were discontinuous, whereas the transparent water-catching layer 4 and the water-catching layer 6 of the present invention have extensions 11 and 12 on at least one side. Transparent water capture M4
This is a point in which seven extensions 11, 12 of and connect the water-catching layer 6.

Although the polymer film such as polyamide resin used for the transparent water-absorbing layer 4 has excellent light transmittance, the polyamide resin itself physically adsorbs moisture, so it tends to absorb moisture due to changes in vapor pressure and temperature. It has the property of easily releasing moisture.

However, the water absorption layer 6 is made of polyamide resin K CaO.

It is coated with a desiccant 5 such as CaSO4, and although it is opaque, this desiccant 5 chemically adsorbs moisture, so once absorbed moisture is not easily released due to changes in vapor pressure or temperature. With ~・ru.

Therefore, in the present invention, in order to take advantage of the characteristics of both the water-catching layers 4 and 6, the transparent water-catching layer 4 and the water-catching layer 6 are connected to the extending portions 11 and 1.
2, the moisture adsorbed by the transparent water-absorbing layer 4 is guided to the water-absorbing layer 6 and absorbed.

In the case shown in FIG. 2, the transparent water-catching layer 4 is extended from the upper left end of the transparent electrode 3 to the lower right end of the lower electrode 1 by extending the extension part 11 of the transparent water-catching layer 4 to the desiccant 5 side of the water-catching layer 6. It is closely related to this.

As a result, the transparent water-absorbing layer 4. Extending portion 1 of transparent water-trapping layer 4
1 physically absorbs moisture, the water-absorbing layer 6 absorbs moisture chemically, and moreover, the transparent water-absorbing layer 4° and the extending portion 11 of the transparent water-absorbing layer 6 absorb the absorbed moisture. The water can be guided to the water trapping layer 6 by the portion 11 and can be chemically absorbed, thereby further reducing the moisture content in the ELD.

The one in FIG. 3 shows another embodiment, and the difference from the one in FIG. 2 is that in the one in FIG. Division 11 was established, but
The one shown in FIG. 3 has two extending portions 11.11 extending from both the left and right ends of the transparent water-trapping layer 4- to approximately the center of the lower electrode 1.

This extension part 11. , 11 absorb moisture in the ELD and reduce the moisture content, and moisture from the sealing portion 10 can also be absorbed by the extension portion 11.11.

The one in FIG. 4 shows another embodiment. In the one in FIG. The parts 11 and 12 are brought into close contact with each other, and the same effect as that shown in FIGS. 2 and 3 can be obtained.

The one in FIG. 5 shows another embodiment. In the one in FIG. 5, extending portions 11.11 are provided at both ends of the transparent water-catching layer 40, and extending portions 12° are provided at both ends of the water-catching layer 60. 12 is provided, and the extending portions 11, 11 and the extending portion 12°12 are adhered to each other with an acrylic adhesive material having a high moisture permeability, etc.
The same effect as in FIG. 3 can be obtained.

In addition, in the case shown in FIG. 5, the luminescent layer 2 is covered with the drying agent 5 of the water-absorbing layer 6, so moisture in the luminescent layer 2 is chemically absorbed by the desiccant 5, resulting in luminescence. The least amount of moisture enters layer 2.

In the embodiments of the present invention, only the use of polyamide resin for the transparent water-absorbing layer 4 and the water-absorbing layer 6 was explained, but instead of this polyamide resin, cellophane, which has excellent hygroscopicity and is thin, may be used. If used, the moisture inside the ELD will be reduced, and the thickness of the ELD itself can be reduced.

A comparison of the general properties of polyamide resin and cellophane will be made as shown in the table below.

The ELD of each of the embodiments shown in FIGS. 2 to 5 described above is 40
℃, 100V, 50H in an atmosphere with relative humidity of 90-95%
When a continuous life test was conducted on z, the half-life of the luminescence intensity was extended as shown in the table below.

Note that the brightness half-life refers to the time taken from the initial brightness of 100 to attenuation to 50.

〔Effect of the invention〕

In the present invention, an extension is provided on at least one of the transparent water-trapping layer and the water-trapping layer, and the two water-trapping layers are brought into close contact with each other, thereby reducing moisture inside the ELD and preventing moisture from entering the light-emitting layer. The lifespan of the light emitting device can be extended.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a conventional ELD, and FIGS. 2 to 5 are sectional views of F and LD according to embodiments of the present invention. DESCRIPTION OF SYMBOLS 1...Lower electrode, 2...Light emitting layer, 3.
...Top electrode, 4...Transparent water-trapping layer, 5.
...Drying agent, 6...Water trapping layer, 9...
...Moisture-proof film, 11.12...Extension Fig. 1 Fig. 2 I5e:i Fig. 3 Fig. 4 2 l 5 6 Fig. 5

Claims (1)

[Claims] A luminescent layer is provided between the lower electrode and the transparent electrode, a transparent water trapping layer is placed above the transparent electrode, a water trapping layer containing a desiccant is placed below the lower electrode, and the electroluminescent layer is covered with a moisture-proof film. 1. An electroluminescent light-emitting device, characterized in that at least one of the transparent water-trapping layer and the water-trapping layer is provided with an extending portion so that both the water-trapping layers are brought into close contact with each other.