JPS6318317B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to an electroluminescent light emitting device (hereinafter referred to as an ELD), and particularly to a moisture-proof structure of an ELD. [Background of the Invention] Conventionally, 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 is known as electroluminescence. FIG. 1 is a cross-sectional view of a conventional flexible 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. The light-emitting layer 2 is formed by dispersing phosphor powder in which ZnS is doped with an activator such as copper or manganese and an inert agent such as chlorine in an organic polymer binder.
As the phosphor powder, rare earth elements, monovalent metals, transition metals, etc. are used. The transparent electrode 3 is formed of a thin film of a metal oxide such as In ₂ O ₃ or SnO ₂ , a thin film of gold or palladium, or a thin film of a metal such as aluminum or copper in which small mesh-like holes are formed. A transparent water-absorbing layer 4 made of a polymer film such as polyamide resin with good light transmittance and high water absorption is placed on the top of the transparent electrode 3, and a desiccant powder such as CaO or CaSO ₄ is placed on the bottom of the bottom electrode 1. A paste containing an organic polymer dissolved in a solvent may be applied, or the desiccant powder may be attached to the lower electrode 1 using an adhesive, or a moisture-absorbing material may be applied to a polymer film such as polyamide resin. These are covered with a moisture-proof film (laminate film) 9 consisting of a heat-fusible film 7 and a water-repellent film 8 made of fluororesin, etc., and the moisture-proof films 9, 9 are bonded together by heat sealing, adhesive, etc. Seal part 1
0 and had a moisture-proof structure. However, the moisture-proofing effect is not sufficient because a small amount of moisture enters from the sealing part 10 through the surfaces of the moisture-proofing films 9, the sealing part 10, and the lead wire extraction part (not shown). Furthermore, since the polymer film such as polyamide resin used for the water-trapping layer has a low dehydration start temperature and easily releases moisture when the ambient temperature rises, the internal humidity tends to increase. For this reason, a desiccant such as CaO or CaSO ₄ , which is difficult to release even at high temperatures, is used below the lower electrode to absorb this moisture. It is not possible to absorb all the moisture released from the water layer 4, and the excess moisture enters the luminescent layer 2, which causes the ELD to emit light in the presence of this moisture. There was a drawback that had a negative effect on the luminescence life of the . [Object of the Invention] The present invention attempts to eliminate such conventional drawbacks, and its purpose is to minimize moisture in the ELD and prevent moisture from entering the light emitting layer. This is an attempt to extend the lifespan of light emitting light. [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,
Both water-trapping layers are in close contact with each other. [Embodiments of the Invention] Examples 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-catching layer 4, and 12 is the water-catching layer 6.
This is an extension of the In such a structure, the conventional
The difference between the ELD and the ELD of the present invention shown in FIGS. 2 to 5 is that in the conventional ELD, the transparent water layer 4 and the water trapping layer 6 are separated, and the transparent water trapping layer 4 and the water trapping layer 6 are separated from each other. were discontinuous, whereas the transparent water-catching layer 4 and water-catching layer 6 of the present invention are provided with extensions 11 and 12 on at least one side, so that the transparent water-catching layer 4 and the water-catching layer 6 are discontinuous.
This is a point in which the space between the two parts is made continuous by the extending parts 11 and 12. The reason is that the polymer film such as polyamide resin used for the transparent water-absorbing layer 4 has excellent light transmittance, but the polyamide resin itself physically adsorbs moisture, so it may absorb moisture due to changes in vapor pressure or temperature. It has the property of easily releasing moisture. However, the water absorption layer 6 is made of polyamide resin with CaO,
It is coated with a desiccant 5 such as CaSO ₄ , 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. It has characteristics. 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 made continuous by the extension parts 11 and 12, and the transparent water-catching layer 4 absorbs water. This moisture is guided to the water trapping 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 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 layer 4 and the extending portion 11 of the transparent water-catching layer 4 physically absorb moisture, and the water-catching layer 6
In this case, the moisture is chemically absorbed, and the moisture absorbed by the transparent water-absorbing layer 4 and the extending portion 11 of the transparent water-absorbing layer 6 is guided to the water-catching layer 6 by the extending portion 11, and the moisture is chemically absorbed. can absorb moisture, further reducing the moisture inside the ELD. The one in Figure 3 shows another embodiment;
The difference from the one in Figure 2 is as follows:
The extension part 11 was provided from the left end of the transparent water-trapping layer 4 to the right end of the lower electrode 1, but in the case of the one in FIG. Two extending portions 11, 11 are provided. Moisture inside the ELD is reduced by the extending portions 11, 11, and moisture from the seal portion 10 can also be absorbed by the extending portions 11, 11. The one in FIG. 4 shows another embodiment. In the one in FIG.
, an extending portion 12 is provided in the water trapping layer 6, and this extending portion 1
Comrades 1 and 12 are placed in close contact, as shown in Figures 2 and 3.
The same effect as in the figure can be obtained. The one in FIG. 5 shows another embodiment.
In the illustrated example, extending portions 11, 11 are provided at both ends of the transparent water-catching layer 4, and extending portions 11 are provided at both ends of the water-catching layer 6.
2, 12 are provided, and the extending parts 11, 11 and the extending parts 12, 12 are adhered to each other with an acrylic adhesive material having a high moisture permeability, etc., and the same effect as the one in Fig. 3 is obtained. can get. In addition, in the case shown in FIG. 5, the luminescent layer 2 is covered with the desiccant 5 of the water absorption layer 6, so that the moisture in the luminescent layer 2 is chemically absorbed by the desiccant 5, so that it does not emit light. 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 has been described, but it is also possible to use cellophane, which has excellent hygroscopicity and is thin, in place of the polyamide resin. Ba
The moisture inside the ELD is lower, and the ELD itself can be thinner. The table below compares the general properties of polyamide resin and cellophane.

[Table] Each of the embodiments shown in Figures 2 to 5 described above
ELD at 100V in an atmosphere of 40℃ and relative humidity of 90-95%,
When we conducted a continuous life test at 50Hz, the half-life of the luminescence intensity was extended as shown in the table below.

〔Effect of the invention〕

In the present invention, an extension is provided on at least one of the transparent water-catching layer and the water-catching layer, and both water-catching layers are brought into close contact with each other.
Moisture inside the ELD is reduced, preventing moisture from entering the light-emitting layer and extending the light-emitting life.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional ELD, and FIGS. 2 to 5 are sectional views of ELDs according to embodiments of the present invention. DESCRIPTION OF SYMBOLS 1...Lower electrode, 2...Light emitting layer, 3...Upper electrode, 4...Transparent water trapping layer, 5...Drying agent, 6...Water trapping layer, 9...Moisture-proof film, 11, 12... Extension.

Claims (1)

[Claims] 1 A light-emitting layer is provided between the lower electrode and the transparent electrode, a transparent water-trapping layer is placed above the transparent electrode, a water-catching layer containing a desiccant is placed below the lower electrode, and the electroluminescent layer is covered with a moisture-proof film. 1. An electroluminescence 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 and the two water trapping layers are brought into close contact with each other.