JPS6041437B2 - electroluminescent device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a light-emitting device that emits light by applying a light field to a light-emitting layer.

When a photoluminescent material such as ZnS, Mn, Cu, Cl, Se, etc. is made and an exposure field is applied, the phenomenon of emitting light is a well-known fact known as electroluminescence (E.L).
Conventionally, such electroluminescent devices have been strongly affected by humidity and have had a very short lifespan.

Figure 1 is a cross-sectional view of an AC electroluminescent device, and 2 is a transparent electrode formed on one surface of a transparent substrate 1 such as a glass substrate or plastic film substrate, and has a sheet resistance of several KQ/□ or less.
It is made of a thin film of metal oxide such as 02 or Sn02, a thin film of metal such as gold or palladium, or aluminum foil with small mesh-like holes.

3 is a counter electrode made of metal powder such as silver dispersed in an organic polymer or inorganic binder, or a metal plate made of aluminum, copper, etc., or a thin film equivalent to the transparent electrode 2. etc. A conventional AC electroluminescent device uses an organic polymer powder consisting of ZnS, an activator such as Cu or Mn, and an activator such as CI or Se between a transparent electrode 2 and a counter electrode 3 that face each other. A light-emitting layer 4 formed by dispersing in a binder or forming a thin film of a saddle phosphor by vapor deposition, sputtering, ion plating, etc. and a high dielectric constant powder such as Ti02 or BaTi03 are mixed in an organic polymer binder. A dielectric layer 5 such as a thin film formed by dispersing the high dielectric constant material or Y203 by vapor deposition, sputtering, ion plating, etc. is sandwiched, and polyethylene 6'a, 6'b is further laminated. The structure is such that the entire structure is covered with moisture-proof protective films 6a and 6b made of polytrifluorochloroethylene or the like. 1st
In the figure, when an AC voltage is applied between both electrodes 2 and 3, an electric field corresponding to the voltage, frequency, and film thickness of each layer is applied to the light emitting layer 4, and light with a wavelength corresponding to the type of saddle light material is generated. do.

Furthermore, there is also a DC field type light emitting device which can be driven by DC voltage without the dielectric layer 5.

If a voltage is applied to the lightning field light emitting device described above in a humid condition, the decomposition of the crab light will proceed in an extremely short period of time and the luminance will drop sharply, so moisture-proof protection is required. Membrane 6a,
However, the protective film is required to have transparency, camouflage, and moisture-proof performance, and trifluorochloroethylene, which has the lowest water vapor permeability among polymer materials, has conventionally been used.
The water vapor permeability of trifluorochloroethylene is 0.025~
It is about 0.055 hrmil/100in2/24hrmil and allows a small amount of moisture to pass through.

The permeated moisture penetrates into the inside of the haze light emitting device, and the brightness life of the haze light emitting device is quite short, resulting in poor reliability. In view of these drawbacks, the present invention provides, on the non-light emitting side,
The device is sealed using a moisture-proof protective film that has been provided with a moisture-proof layer made of metal foil in order to improve its brightness life.

The present invention will be explained below based on examples.

Example 1 FIG. 2 is an explanatory diagram of Example 1, in which 1 to 6'b have the same structure as the conventional one, and 6a is polytrifluorochloroethylene to which polyethylene 6'a is laminated and bonded.

6'b is an adhesive layer made of 80% polyethylene to facilitate adhesion to 6'a.

No. 7 is a moisture-proof layer to prevent humidity, and No. 20-1 AI foil was used.

Further, 8 is a polyester film of 25 which serves as a retaining layer and maintains the strength of the moisture-proof protective film. Moisture-proof protective film is polyethylene 6'b, AI7, polyester 8,
0 to 0.
．． It has a water vapor transmission rate of 02 evening/100 solutions/24 hrmil. Example 2 FIG. 3 is an explanatory diagram of Example 2, and numeral 9 indicates an insulating layer using polyester.

The insulating layer 9 is provided to prevent a terminal for applying a haze field from short-circuiting with the moisture-proof layer 7 when the haze light emitter is heated and crimped and sealed with a moisture-proof protective film. The moisture-proof protective film used here is the same as in Example 1, in which the thicket layer 6'b, the insulating layer 9, the moisture-proof layer 7, and the retaining layer 8 are laminated and adhered in this order. Example 3 FIG. 4 is an explanatory diagram of Example 3, in which the moisture-proof protective film on the back side of Example 2 does not have a retaining layer and an insulating layer.

1. Using a polyester film as a transparent insulating substrate to confirm the effect of the moisture-proof protective film according to the present invention. T. 0
It had a transparent electrode, a light-emitting layer made of ZnS,C, CI-based crab photon powder dispersed in cyanoethylated cellulose, and a dielectric layer made of Ti02 dispersed in cyanoethylated cellulose, and an aluminum plate was used as the counter electrode 3. Using the same electroluminescent body as the conventional Kameba light emitting device, which has a structure in which an AC electroluminescent body is sandwiched from above and below with a polytrifluorochloroethylene film laminated with polyethylene and protected against moisture by heat and pressure bonding, the light emitting side is protected against moisture. The film was a polytrifluorochloroethylene film laminated with polyethylene and the non-emissive side was a moisture-proof protective film according to each of the above-mentioned examples.
When compared in the OV50HZ humidity load test, the results of the present invention were found to have a luminance half-life twice as long as the conventional product (30 field hours) in each example, and the effect was remarkable. Although polyester is used as the retaining layer 8 in this embodiment, other polymer films having similar melting points may be used.

Similar effects can be obtained by forming the moisture-proof layer 7 by laminating and adhering Zn, Cu, Cr, Hi-Cr, etc. other than AI. Furthermore, a low melting point polymer compound or hot melt adhesive may be used as the adhesive layer 6'b, or an insulating layer 9'b may be used.
It goes without saying that the same effect can be obtained even if a polymer film other than polyester having a melting point comparable to or higher than polyester is used. As described above, in the present invention, an electroluminescent device is sealed using a moisture-proof protective film on which a moisture-proof layer made of metal foil has been provided in advance, thereby preventing the intrusion of moisture and extending the brightness life. can. Furthermore, the sealing work is facilitated by using a moisture-proof protective film that is pre-laminated with metal foil.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional side view of the main parts of a conventional electroluminescent device.
The figure is a sectional side view of a main part of a hazy field light emitting device according to the present invention. 1...Transparent insulating substrate, 2...Transparent electrode, 3...
...Counter electrode, 4...Light emitting layer, 5...
Dielectric layer, 6a, 6b... Moisture-proof protective film, 6
'a, 6'b...Adhesive layer, 7...Moisture-proof layer, 8...Retaining layer, 9...Insulating layer. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. An electroluminescent device comprising two electrodes facing each other, at least one of which is transparent, and a phosphor layer sandwiched between the two electrodes, which are sealed with a moisture-proof protective film. An electroluminescent device characterized in that it is sealed using a moisture-proof protective film provided with a moisture-proof layer made of metal foil. 2. The electroluminescence according to claim 1, characterized in that the moisture-proof protective film is provided with a moisture-proof layer made of metal foil, and an insulating layer for preventing short circuit between the metal foil and the electrode. Device. 3. A patent claim characterized in that the moisture-proof protective film is provided with a moisture-proof layer made of metal foil, an insulating layer for preventing short circuit between the metal foil and the electrode, and a holding layer for reinforcement. An electroluminescent device according to the first term in the range.