JPH0869878A - Dispersion type el device - Google Patents

Abstract

PURPOSE: To prevent the degradation of a conductive film caused by decomposition and degeneration by forming both surfaces of a transparent conductive film out of a moistureproof thin film. CONSTITUTION: A reflecting insulating layer 3 having a thickness of about 30μm formed by dispersing white powder having high permitivity such as barium titanate in an organic binder 2 such as cyano ethyl pullulan and a light emitting layer 5 of about 60μm formed by dispersing a phosphor powder 4 in the binder 2, are formed on Al foil 1 having a thickness of about 100μm, and an EL element 19 having a thickness of about 200μm is manufactured by mutually sticking moisture resistant transparent conductive films 18 by forming metallic oxide thin films 17 having a thickness of about 1μm as a moistureproof thin film by a method such as evaporation and sputtering on both surfaces of a transparent conductive film 8 on which a transparent conductive film 7 having a thickness of about 2μm such as ITO as a transparent electrode is formed on a single surface of a transparent film 6 having a thickness of 50μm, and lead out terminals 10 and 11 are respectively connnected to and installed on a back electrode 1 and the film 7. In this way, a thin type dispersion type EL 16 having a thickness of about 200μm for which a moistureproof skin film is made unnecessary is obtained. Since the metallic oxide thin film 17 exists between the film 7 and the layer 5, infiltration of moisture is cut off, so that the film 7 is not degraded by decomposition and degeneration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispersion type EL device, and more particularly to a dispersion type EL device which does not require a moisture-proof outer film and is excellent in moisture resistance.

[0002]

2. Description of the Related Art Recently, a dispersion type EL has been widely used as a sheet-like light emitting device such as a backlight of a liquid crystal display device. As shown in FIG. 4, this dispersion-type EL device has a structure in which a high-dielectric-constant white powder such as barium titanate is dispersed in an organic binder such as cyanoethyl pullulan on an aluminum foil 1 having a thickness of about 100 μm serving as a back electrode. A reflective insulating layer 3 having a thickness of 30 μm and a light emitting layer 5 having a thickness of about 60 μm in which a phosphor powder 4 is dispersed in an organic binder 2 such as cyanoethyl pullulan are sequentially formed, and a polyethylene terephthalate (hereinafter referred to as PET) having a thickness of about 50 μm is formed. On one surface of the transparent film 6 such as a film, indium oxide, tin oxide, or a compound of indium oxide and tin oxide (these are referred to as ITO hereinafter).
A transparent conductive film 8 having a 2 μm thick transparent conductive film 7 formed thereon is bonded to form an EL element 9 having a thickness of approximately 200 μm.
1 are connected to the back electrode 1 and the transparent conductive film 7, respectively, and are covered and sealed with a moisture-proof outer film 12 having a thickness of 250 μm, such as trifluorochloroethylene.

However, since the dispersion type EL having the above-described structure has a complicated laminated structure, it is inevitable that the manufacturing process and the manufacturing cost are disadvantageous, and the thickness of the entire device becomes too thick, that is, approximately 700 μm. there were. Moreover, when the moisture-proof outer film 8 is covered and sealed, foreign matter adheres and mixes due to charging,
There is also a problem that defective sealing and poor appearance occur, and warpage occurs due to the difference in thermal expansion between the EL element 9 and the moisture-proof outer film 12. In order to solve this problem, JP-A-3-238792 discloses that the adhesion between the transparent conductive film 7 and the light emitting layer 5 is improved and the moisture resistance of the transparent film 6 is improved, as shown in FIG. Therefore, a dispersion type EL is disclosed in which the metal oxide layer 13 is provided on the transparent conductive film 7 and the transparent conductive moisture-proof film 14 having the functions of both the transparent film and the moisture-proof outer film is used. On the other hand, JP-A-4-264
As disclosed in Japanese Patent No. 389, the EL element 9 as shown in FIG. 6 is immersed in a metal alkoxide solution, dried, and then subjected to low temperature plasma treatment to form a transparent moisture-proof film 15 of metal oxide. And distributed type E with improved moisture resistance
L is also proposed.

[0004]

However, the use of the transparent conductive moisture-proof film does not solve the above-mentioned problems due to the simplification of the laminated structure, but the moisture which penetrates from the outside through the transparent film. Since it is not possible to prevent the decomposition of the transparent conductive film due to, it is necessary to use a film with high moisture resistance such as trifluoroethylene chloride as the material of the transparent film. In addition, it is difficult to form the transparent conductive film and it is expensive, so that there is a problem that the cost cannot be reduced. In addition, a transparent moisture-proof film made of a metal alkoxide solution is used as an E
Although the moisture resistance of the one formed on the entire surface of the L element is improved by two to three times, the moisture-proof outer film cannot be omitted.
Problems due to complicated laminated structures cannot be solved. In addition, there is a problem that the decomposition of the transparent conductive film due to the moisture contained in the organic binder of the light emitting layer or the reflective insulating layer cannot be prevented. An object of the present invention is to solve the above problems at the same time, to provide a high-quality and inexpensive dispersion type EL that is thin, simplifies the laminated structure by eliminating the need for an expensive moisture-proof outer film, and has significantly improved moisture resistance. To do.

[0005]

Means for Solving the Problems A light emitting layer in which a phosphor powder is dispersed in an organic binder is provided between a transparent electrode and a back electrode of a transparent conductive film having a transparent conductive film formed on one surface of a transparent film, and a reflective insulating film. A dispersion type EL having a layer, wherein the moisture-proof thin film is formed on both surfaces of the transparent conductive film, and the moisture-proof thin film is a metal oxide thin film. And the phosphor powder is coated with a metal oxide having moisture resistance.

[0006]

According to the above construction, since the moisture-proof thin films are formed on both sides of the transparent conductive film, invasion of moisture into the transparent conductive film from the outside or inside (for example, an organic binder such as a light emitting layer)
The invasion of water contained in is blocked by the moisture-proof thin films on both sides, so that the transparent conductive film is not decomposed or deteriorated due to alteration. Moreover, since the moisture-proof thin film is formed between the transparent conductive film and the light emitting layer, the adhesion between the light emitting layer and the transparent conductive film can be improved, and the moisture resistance of the transparent conductive film can be significantly improved. Thus, it is possible to realize a dispersion type EL having a simple laminated structure that does not require a moisture-proof outer film.

In addition, the transparent conductive film is made of inexpensive PET.
A thin, low-cost dispersion type that can form a transparent conductive film on a film, and by using a moisture-proof thin film as a metal oxide thin film, the transparent conductive film can be easily formed, and the decomposition of the transparent conductive film by moisture is prevented. EL can be provided. further,
By covering the phosphor powder with a metal oxide having moisture resistance, deterioration of the phosphor due to moisture can be prevented, so that a dispersion type EL having a longer life can be realized.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. The dispersion type EL of the present invention is characterized in that a moisture-proof thin film is formed on both surfaces of a transparent conductive film. That is, as shown in FIG. 1, the distributed type E according to one embodiment of the present invention.
L16 is a reflective insulating layer 3 having a thickness of about 30 μm in which a high-dielectric-constant white powder such as barium titanate is dispersed in an organic binder such as cyanoethyl pullulan on an aluminum foil 1 having a thickness of about 100 μm serving as a back electrode, and An approximately 60 μm thick light-emitting layer 5 in which phosphor powder 4 is dispersed in an organic binder 2 such as cyanoethyl pullulan is sequentially formed, and a transparent film (for example, PET film) 6 having a thickness of 50 μm is formed on one surface of a transparent electrode such as ITO or the like. A metal oxide thin film (for example, a silicon oxide thin film) 17 having a thickness of about 1 μm was formed as a moisture-proof thin film on both surfaces of the transparent conductive film 8 on which the transparent conductive film 7 having a thickness of 2 μm was formed, by a method such as vapor deposition and sputtering. A moisture-resistant transparent conductive film 18 is attached to form an E film having a thickness of about 200 μm.
An L element 19 is prepared, and lead terminals 10 and 11 are connected to the back surface electrode 1 and the transparent conductive film 7 and attached to the EL element 19, respectively.

With this structure, a thin dispersion type EL 16 having a thickness of about 200 μm can be obtained which does not require a moisture-proof outer film. Moreover, the transparent conductive film 7 and the light emitting layer 5
Since the metal oxide thin film 17 is formed between
Adhesion between the light emitting layer 5 and the transparent conductive film 7 can be improved, and moisture entering the transparent conductive film 7 from the outside through a transparent film such as a PET film or moisture contained inside an organic binder or the like. Since the metal oxide thin films 17 on both surfaces block the invasion of the transparent conductive film 7, the transparent conductive film 7 is not decomposed and deteriorated due to alteration or the like. Further, when the transparent conductive film 7 is formed on the PET film 6 as the transparent conductive film and the metal oxide thin film 17 having moisture resistance is a silicon oxide thin film, the transparent conductive film 7 can be easily formed. .
As a second embodiment of the dispersion type EL device of the present invention, as shown in FIG. 2, a so-called capsule in which the light emitting layer of the first embodiment described above is coated with a phosphor powder with a moisture-proof metal oxide. There is a dispersion type EL 22 having a structure in which the phosphor powder 20 is replaced with a light emitting layer 21 dispersed in an organic binder 2 such as cyanoethyl pullulan.

In the dispersion type EL 22 of this embodiment, the use of the encapsulated phosphor powder 20 makes it possible to prevent the phosphor from deteriorating due to the moisture contained in the organic binder and the like, and to make the transparent conductive film 7 As in the case of the first embodiment, since it is protected from moisture entering from inside and outside, the life can be further extended. Further, as a third embodiment of the dispersion type EL of the present invention, as shown in FIG. 3, the dispersion type EL 16 or 22 of the first or second embodiment is covered with a transparent protective film 23. There is EL24.

The dispersion type EL 24 of this embodiment has a metal oxide thin film 17 on the outer surface of a moisture resistant transparent conductive film 18, a back electrode 1, a transparent conductive film 7 and external leads 10, 1.
Since the connection portion with 1 is protected by the transparent protective film 23, the reliability can be further increased. The example in which the PET film is used as the transparent film 6 and the silicon oxide thin film is used as the moisture-proof metal oxide thin film 17 has been described above, but the present invention is not limited to this, and the transparent film 6 may be polyimide or polyether sulfone. Various plastic films such as, polyetherketone, polycarbonate, polypropylene, polyamide, polystyrene, and polyacrylic can be used.

Further, as the moisture-proof thin film 17, titanium oxide, aluminum oxide, zirconium oxide, tantalum oxide, a metal oxide having a high dielectric constant (for example, barium titanate,
An oxide thin film made of various metal oxides such as lead titanate, strontium titanate, zirconium titanate) or a mixture thereof can be used. The thickness of the metal oxide thin film is not limited to 1 μm, and may be 0.1 μm to 3 μm in consideration of brightness, dielectric constant of metal oxide, adhesion, moisture resistance, transparency, productivity and the like. It is desirable to select within the range. A material having a higher dielectric constant is less expensive in voltage and less in luminance reduction, so that it can be formed thicker, which is advantageous in terms of moisture resistance. Further, it is effective in terms of moisture resistance and brightness characteristics that the moisture-proof thin film formed on the outer side of the transparent conductive film is thicker than the moisture-proof thin film on the inner side. Of course, the inner and outer materials may be different. For example, the inner side has a good adhesion to the light emitting layer, and the outer side has a high strength and is not easily scratched. In each of the embodiments shown in FIGS. 1 to 3, the lead-out terminals 10 and 11 are connected to the back electrode and the transparent conductive film, respectively, but in the case of the distributed EL in which the lead-out terminals are not connected, the surface is exposed. The conductive portion of may be formed on each electrode.

[0013]

According to the present invention, since the moisture-proof thin film is formed on both sides of the transparent conductive film, the invasion of moisture into the transparent conductive film from the outside or the moisture contained therein is prevented from occurring on both sides. It is blocked by the metal oxide thin film, so that the transparent conductive film is not decomposed or deteriorated due to alteration. Moreover, since the metal oxide thin film is formed between the transparent conductive film and the light emitting layer, the adhesion between the light emitting layer and the transparent conductive film can be improved, and the moisture resistance of the transparent conductive film is significantly improved. Thus, it is possible to realize a dispersion type EL having a simple laminated structure that does not require a moisture-proof outer film.

Also, the transparent conductive film is made of inexpensive PET.
A transparent conductive film is formed on the film, and the moisture-proof thin film is a metal oxide thin film, so that the transparent conductive film can be easily formed, and the transparent conductive film is prevented from being decomposed by moisture. Dispersion type EL can be provided. Further, by encapsulating the phosphor powder, deterioration of the phosphor due to moisture can be prevented, so that a dispersion type EL having a longer life can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a dispersion type EL according to an embodiment of the present invention.

FIG. 2 is a sectional view of an essential part of a dispersion type EL according to a second embodiment of the present invention.

FIG. 3 is a sectional view of an essential part of a dispersion type EL according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a conventional dispersion type EL.

FIG. 5 is a cross-sectional view of a main part of a conventional second example of a dispersion-type EL device.

FIG. 6 is a sectional view of a main part of a conventional dispersion type EL of a third example.

[Explanation of symbols]

 1 Backside Electrode 2 Organic Binder 3 Reflective Insulating Layer 4 Phosphor Powder 5,21 Light Emitting Layer 6 Transparent Film 7 Transparent Conductive Film (Transparent Electrode) 8 Transparent Conductive Film 10, 11 Lead Terminals 16, 22, 24 Dispersion EL 17 Metal Oxide thin film (moisture-proof thin film) 18 Moisture-resistant transparent conductive film 23 Transparent protective film

Claims (3)

[Claims] 1. A dispersion type EL comprising a reflective insulating layer and a light emitting layer in which a phosphor powder is dispersed in an organic binder between a transparent conductive film having a transparent conductive film formed on one surface of a transparent film and a back electrode. A dispersion-type EL device characterized in that a moisture-proof thin film is formed on both sides of the transparent conductive film.
apparatus. 2. The dispersion type EL device according to claim 1, wherein the moisture-proof thin film is a metal oxide thin film. 3. The dispersion type EL device according to claim 1, wherein the phosphor powder is a phosphor powder coated with a metal oxide having moisture resistance.