JPH02112197A - Electroluminescence lamp - Google Patents

Abstract

PURPOSE:To improve the life characteristic and the reliability of a lamp by using as a binder material for dispersing insulating substance and light emitting bodies a mixture of a binder excellent in heat resistance and a binder excellent in adhesivity. CONSTITUTION:A mixture of a binder material such as cyanoethylcellulose having a high softening point and excellent heat resistance and a binder such as cyanoethylsaccharose having a low softening point and excellent bonding characteristic has the dielectric constant, the life characteristic Bo-Time, and the tensile strength as shown in the figure. An electroluminescence lamp using a binder of the mixture ratio of cyanoethylcellulose to cyanosaccharose of 1.0 has a sufficient bondage strength between a transparent electrode and a light emitting layer and improves high temperature life characteristic without impairing the EL characteristic at normal temperatures.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electroluminescent lamp, and more particularly to a technique for improving heat resistance using a binder in a distributed type electroluminescent lamp.

Conventionally, an organic dispersion type electroluminescent lamp 28, as shown in FIG. body(
For example, the insulating layer 22 and the light-emitting layer 23 are formed by sequentially coating zinc sulfide (activated with copper, phosphor), non-anoethyl cellulose, etc. dispersed in a mechanical binder, and then a current collecting band is placed on top of them. A transparent electrode 24 made of a printed transparent conductive film or the like is pasted on the hygroscopic film 25 from above and below.
It has a structure in which an electroluminescent element 27 covered with (for example, nylon 6 (trademark of DuPont)) is hermetically sealed from above and below with a moisture-proof outer film (for example, trifluorochloroethylene, etc.) 26.

Therefore, in the electroluminescent lamp having the above structure, the following materials are used as the organic binder for dispersing the luminescent material and the insulator, depending on the manufacturing method. In other words, 2
When applying heat to around 00"C to seal the outer skin, binders such as cyanethylcellulose, polyvinylidene fluoride, and cyanoethylpolyvinyl alcohol are used. These have the following characteristics: 1) high softening point; 2) There is relatively little change in dielectric constant at high temperatures.3) High dielectric constant.

In addition, when sealing the outer shell at a relatively low temperature as in the lamination method, binders such as cyanoethyl pullulan, cyanethylhydroxyethylcellulose, and cyanethylsaccharose are used, and their characteristics include 1) low softening point and good adhesive properties; Are better. 2) The life span decreases because the dielectric constant increases at high temperatures. 3) High dielectric constant. etc.

Here, in an electroluminescent lamp of the type in which a transparent electrode is bonded to a light emitting layer, when a binder such as cyan ethyl cellulose, polyvinylidene fluoride, or cyan ethyl polyvinyl alcohol is used, the adhesive force between the transparent electrode and the light emitting layer is weak. It is easy to cause serious defects such as non-emission due to peeling. Furthermore, when a binder such as cyanoethyl pullulan, cyanethylhydroxyethylcellulose, or cyanoethylsaccharose is used, the adhesion between the transparent electrode and the light emitting layer is good, and although it does not cause the serious defect of non-emission due to peeling, the dielectric strength of the binder under high temperature There were problems such as an increase in efficiency, an excessively high brightness, and a reduction in lifespan.

In order to solve the above problems, the present invention uses a binder with a high softening point (for example, cyanoethyl cellulose) and a binder with a low softening point (for example, cyanoethyl cellulose) as the binder material used for the light emitting layer and the insulating layer.
For example, it is characterized by being mixed with cyanethyl sucrose).

However, by using a mixture of a binder with excellent adhesiveness and a binder with excellent heat resistance, the adhesive strength between the transparent electrode and the light emitting layer can be increased to 1.
It is possible to improve the reliability of electroluminescent lamps by improving their lifetime characteristics at high temperatures while keeping them within minutes.

Cheapness of moxibustion An embodiment of the present invention will be described.

FIG. 1 is a sectional view of an electroluminescent lamp according to an embodiment of the present invention, and an electroluminescent lamp having such a structure is manufactured as follows. An insulator (e.g., high dielectric powder such as barium titanate) 9 and a phosphor (e.g., a phosphor made of zinc sulfide activated with copper) 7 are placed on an aluminum foil 1 serving as a back electrode, and an organic binder (e.g., cyanoethyl cellulose) and cyanoethyl saccharose at a ratio of 1:1) 8.
The insulating layer 25 and the light emitting layer 3 are formed by sequentially applying the dispersed materials in the insulating layer 25 and the light emitting layer 3. Then, a transparent conductive film 4, which is a transparent electrode with a current collecting band printed thereon, is laminated on top of it, and a hygroscopic film (for example, nylon 6) is attached from above and below.
The electroluminescent element 11 covered with DuPont Co., Ltd. trademark) 5.5 is further sandwiched between moisture-proof outer film (e.g. trifluorochloroethylene) 6, 6 from above and below, and the outer film is formed by pressing with hot rolls. The peripheral overlapping portion of the film 6.6 is welded and hermetically sealed.

Next, Figure 2 shows the temperature characteristics of the dielectric constant of cyan ethyl cellulose, Figure 3 shows the temperature characteristics of the dielectric constant of /anoethyl saccharose, and Figure 4 shows the temperature characteristics of the dielectric constant of cyan ethyl cellulose and /anoethyl saccharose at a ratio of 1:2.1:1, respectively. .The temperature characteristics of the dielectric constant of the mixture at a ratio of 2:1 are shown. It can be seen from FIGS. 2 to 4 that the addition of cyanoethyl cellulose to cyanoethyl saccharose suppresses the increase in dielectric constant at high temperatures. Further, FIG. 5 shows the life characteristics of an electroluminescent lamp using these mixed binders at high temperature (70° C.). That is, by adding the same amount of cyanoethyl cellulose to cyanethyl saccharose, the life at high temperature can be improved by about 1.3 times compared to the conventional method using only cyanoethyl saccharose.

Next, FIG. 6 shows the adhesion strength between the transparent electrode and the light-emitting layer when cyan ethyl saccharose/anoethyl saccharose and cyan ethyl cellulose mixture and cyan ethyl cellulose were used. From this, by adding nanoethylcellulose to cyanethylsaccharose, the ratio of cyanethylcellulose/Noafail saccharose decreases to 1.0.
In addition, the adhesive strength is at the same level as when cyanoethyl saccharose is used alone, and sufficient adhesiveness between the transparent monopole and the light emitting layer can be ensured.

That is, in an electroluminescent lamp using a mixed binder with a cyanoethyl cellulose/cyanoethyl saccharose ratio of 1.0, sufficient adhesion strength between the transparent electrode and the light emitting layer is maintained;
This does not impair the EL characteristics at room temperature, and can improve the life characteristics at high temperatures.

Next, other embodiments according to the present invention will be described. 7th
The figure is a cross-sectional view of an electroluminescent lamp using a glass substrate.
An electroluminescent lamp with such a structure is made as follows. A light emitting layer, an insulating layer, and a back electrode are sequentially formed on a glass substrate with ITO, which serves as a substrate, and an adhesive (for example, epoxy resin) is applied to the periphery, and the glass substrate is hermetically sealed.

In the above-mentioned electroluminescent lamp, since there is no need to attach a transparent electrode, the cyanethyl cellulose/cyanoethyl cellulose ratio can be made more than 1.0, thus improving the life characteristics at higher temperatures. It is possible,
In addition to the good sealing properties of glass, it is possible to provide an electroluminescent lamp with even greater reliability.

According to the present invention, by mixing a material with excellent adhesiveness and a material with excellent high temperature properties into a binder for dispersing an insulator and a luminescent material, the adhesive strength and adhesion at room temperature are improved. The life characteristics at high temperatures can be improved without impairing the EL characteristics.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of essential parts of an electroluminescent lamp which is an embodiment of the present invention. Figure 2 shows the dielectric constant-temperature characteristics of cyanethylcellulose, Figure 3 shows the dielectric constant-temperature characteristics of cyanethyl saccharose, and Figure 4 shows the dielectric constant-temperature characteristics of a mixed system of cyanethylcellulose and nanoethylsanocallose. . FIG. 5 shows the life characteristics of the electroluminescent lamp according to the present invention under temperature control, and FIG. 6 shows the adhesive strength between the transparent electrode and the light emitting layer. FIG. 7 is an enlarged sectional view of a main part of an electroluminescent lamp using glass for the bath caning. FIG. 8 is an enlarged sectional view of the main part of a conventional electroluminescent lamp. 2... Insulating layer, 3... Light emitting layer, 4... Transparent electrode, 7... Phosphor, 9... Insulator, 11... Electroluminescent element, I2... Electroluminescent lamp. J ro Am・F Teken-← Bag-・Masu/111mu

Claims (1)

[Scope of Claims] In an electroluminescent lamp in which an electroluminescent element in which an insulating layer and a light emitting layer are sandwiched between a back electrode and a transparent electrode is hermetically sealed with an outer skin film, the binder material for dispersing the insulator and the phosphor has heat resistance. An electroluminescent lamp characterized by using a mixture of an excellent binder and a binder with excellent adhesive properties.