JPH02234389A - Distributed el element - Google Patents

Abstract

PURPOSE:To improve luminous efficiency by covering a luminous layer, a dielectric layer and a back electrode on a transparent electrode with a plastic sheet, and sealing the outer periphery of the plastic sheet with a substrate and a sealing material. CONSTITUTION:A luminous layer 3, a dielectric layer 4 and a back electrode 5 formed on a transparent electrode 2 are covered by a plastic sheet 6 stuck with an adhesive on the inner face. When the circumference of the luminous layer 3, dielectric layer 4 and back electrode 5 is sealed by a fluid sealing material 7 such as epoxy resin, the plastic sheet 6 is covered on them, thus the sealing material 7 does not infiltrate into the porous luminous layer 3, dielectric layer 4 and back electrode 5. The decrease of the effective luminous area due to the infiltration of the sealing material is sufficiently suppressed, and luminous efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a distributed EL device, and more particularly to a distributed EL device that has good luminous efficiency and excellent reliability. [Prior Art] In general, a dispersion type EL element has a light-emitting layer made of a transparent electrode made of indium-tin oxide or the like formed on a transparent substrate, a light-emitting layer in which a phosphor is dispersed in a high dielectric constant binder resin, and a titanic acid A dielectric layer in which a high dielectric constant inorganic material such as barium is dispersed in a high dielectric constant binder resin is sequentially laminated, a back electrode such as an At electrode is further provided on the dielectric layer, and these are connected to a substrate and an epoxy resin. It is made by sealing with a sealing material such as resin. (Japanese Patent Publication No. 62-38838) [Problems to be Solved by the Invention] However, the light-emitting layer and dielectric layer formed on the transparent electrode, as well as the back electrode such as the At electrode formed by vapor deposition of AI, are all Because they are porous, when sealing their surroundings with a fluid sealing material such as epoxy resin, the sealing material may get inside them and the voltage for emitting light may no longer be applied. However, the problem is that the area around the light emitting part may not emit light or there may be areas with low brightness, resulting in a reduction in the effective light emitting area. [Means for Solving the Problems] The present invention has been made as a result of various studies in view of the current situation. By sealing the light-emitting layer, dielectric layer, and back electrode with the substrate and the sealing material with the intervening layer, the fluidity of the sealant such as epoxy resin is prevented from entering the light-emitting layer, dielectric layer, and back electrode. , the reduction in the light emitting area of the distributed EL element is suppressed and the light emitting efficiency is improved.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an explanation will be given with reference to drawings showing an example of a distributed EL element of the present invention.

FIG. 1 shows a cross-sectional view of an example of the dispersion type EL element of the present invention, l is a transparent glass plate, and a transparent electrode 2 made of indium-tin oxide or the like is formed on this glass plate 1. has been done.

3, on this transparent electrode 2, a luminescent paint prepared by mixing and dispersing a phosphor, a high dielectric constant binder resin, and an organic solvent is applied;
A light emitting layer is formed by drying, and a dielectric paint prepared by mixing and dispersing a high dielectric constant inorganic substance such as barium titanate, a high dielectric constant binder resin, and an organic solvent is further applied on this light emitting layer 3. After drying, the dielectric layer 4 is laminated.

Further, on this dielectric layer 4, a back electrode 5 made of aluminum or the like is formed by aluminum vapor deposition or the like, and a light emitting layer 3 and a dielectric layer 4 formed on these transparent electrodes 2 are formed.
The back electrode 5 is covered with a plastic sheet 6 having an adhesive attached to its inner surface.

7 is a sealing material made of epoxy resin or the like for sealing the light emitting layer 3, dielectric layer 4 and back electrode 5; 8 is a glass plate laminated on the blue electrode 5 via the plastic sheet 6;
The light emitting layer 3, dielectric layer 4, and back electrode 5 are sealed with a glass plate 8 and a sealant 7 via a plastic sheet 6.

Therefore, when the periphery of the light-emitting layer 3, the electric layer 4, and the back electrode 5 is sealed with a fluid sealing material 7 such as an epoxy resin, the plastic sheet 6 is interposed, so the sealing material 7 is a porous light emitting layer 3, a dielectric layer 4 and a back electrode 5
It does not get inside, and the decrease in the effective light emitting area due to the infiltration of the sealing material is sufficiently suppressed, and the light emitting efficiency is improved.
A dispersion type EL element A with high brightness and excellent chain properties can be obtained.

Here, as the plastic sheet 6, a sheet formed of an impermeable resin such as a polyolefin resin such as polypropylene or polyethylene, a fluorine resin, a polyester resin, or a vinyl chloride resin is preferably used. The adhesive material that adheres to the inner surface of the plastic sheet 6 includes silicone adhesive, rubber adhesive, and acrylic adhesive that have excellent adhesion to the transparent electrode 2, light emitting layer 3, dielectric layer 4, back electrode 5, etc. Pressure-sensitive adhesives such as are preferably used. Then, the plastic sheet 6 with the adhesive material attached to the inner surface is heat-pressed and adhered to the back electrode 5, the dielectric layer 4, the light emitting layer 3, and the transparent electrode 2.
Cover these.

In addition, the transparent electrode 2 is made of indium-tin oxide, I
nz O. , SnO. , Au, etc., is formed by electron beam evaporation or sputtering.

Furthermore, examples of the phosphor used in the light emitting layer 3 include ZnS, ZnSe, ZnS-Se, ? dS, CdS
e, CdS-Se, etc., Cu, CI, B
Those activated with one or more elements such as rzMn as a luminescent center are preferably used, and the high dielectric constant binder resins include, for example, cyanoethylated cellulose, cyanoethylated pullulan, cyanoethylated sucrose. etc. are preferably used. Further, as the organic solvent, any of the organic solvents generally used in the light-emitting layer of a dispersed EL element, such as dimethylformamide and n-methyl-2-pyrrolidone, are preferably used.

Further, as the high dielectric constant inorganic compound used in the dielectric layer 4, for example, barium titanate, lead titanate, titanium dioxide, etc. are preferably used, and the high dielectric constant binder resin, organic solvent, etc. are used in the light emitting layer 3. Any of the same ones used are preferred.

Further, the back surface electrode 5 formed on the dielectric layer 4 includes metal electrodes such as Au, MoSCr, etc. in addition to Al, and metal oxide electrodes such as Inzowl and SnO■.
It is formed by a resistance heating method or the like in addition to a vacuum evaporation method.

Further, as the sealing material 7, silicone resin or the like is used in addition to epoxy resin.

The thus formed distributed EL element A is driven by connecting the transparent electrode 2 and the back electrode 5 to an AC power source 9, as shown in FIG.

〔Example〕

Next, embodiments of the invention will be described.

Example I A luminescent paint was prepared by mixing and dispersing 30 parts by weight of a phosphor consisting of ZnS:Cu, CI with 10 parts by weight of cyanoethylated bulluran and 100 parts by weight of dimethylformamide. 1.1m thick
It was coated onto a transparent electrode 2 made of indium-tin oxide formed on a transparent glass plate 1 of 100 m in diameter, and dried at 100° C. for 2 hours to form a light-emitting layer 3 with a thickness of 50 μm.

Next, 50 parts by weight of barium titanate was mixed with 10 parts by weight of cyanoethylated pullulan and 10 parts by weight of dimethylformamide.
A dielectric paint was prepared by mixing and dispersing the dielectric paint with the 0-layer image, and this dielectric paint was applied onto the light emitting layer 3 and dried at 100°C for 4 hours to form a dielectric layer 4 having a thickness of 20 μm.

After that, aluminum is deposited on this dielectric layer 4,
A back electrode 5 made of aluminum with a thickness of 500 nm is formed, and a polypropylene film 6 with a silicone adhesive attached to the inner surface is applied from above the back electrode 5 around the dielectric layer 4 and the light emitting layer 3. and coated with transparent electrode 2.
coated on top. Then, these were sealed with a glass plate 8 and a sealing material 7 made of epoxy resin to produce a distributed EL element A as shown in FIG.

Comparative Example 1 A dispersion type E as shown in FIG.
An L element was manufactured.

The transparent electrode 2 and back electrode 5 of the distributed EL device obtained in each example and comparative example were connected to an AC power source 9,
The initial brightness was measured by driving with a 400 Hz pulse wave at 20° C. and 60% RH.

Table 1 below shows the results.

Table 1, FIG. 1 is a cross-sectional view showing an embodiment of the dispersion type EL element of the present invention, and FIG. 2 is a cross-sectional view of a conventional dispersion type EL element.

■...Glass plate (transparent substrate), 2...Transparent electrode, 3
...Light emitting layer, 4...Dielectric layer, 5...Back electrode, 6
...Plastic sheet, 7... Sealing material, 8...
Glass plate (substrate), A... Monodispersed EL element Patent applicant Hitachi Maxell, Ltd. [Effects of the invention] As is clear from Table 1 above, the dispersive EL element obtained by this invention (Example 1 ) is a conventional distributed EL element (
Compared to Comparative Example 1), the initial luminance was higher, which indicates that the dispersion type EL element obtained by the present invention has good luminous efficiency and excellent brightness.

[Brief explanation of the drawing]

Claims (1)

[Claims] 1. A transparent electrode is provided on a transparent substrate, a light emitting layer and a dielectric layer are laminated on the transparent electrode, a back electrode is further provided on the dielectric layer, and the light emitting layer, dielectric layer and back electrode are covered with a plastic sheet, A distributed EL element in which the outer periphery of a plastic sheet is further sealed with a substrate and a sealing material.