JP2791354B2 - EL element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EL device.

[0002]

2. Description of the Related Art Among conventionally used EL elements, it is possible to eliminate the need to hold both sides of an EL element with a moisture-proof film on both sides of the EL element. Accordingly, an EL element which is thin and can be downsized has been developed.

[0003] This EL element has a transparent electrode layer 51a on the back surface.
Is formed, a light emitting layer 52 formed on the back surface of the transparent electrode film 51, an insulating layer 53 formed on the back surface of the light emitting layer 52, and a back electrode layer 54 formed on the back surface of the insulating layer 53. The electrically insulating resin layer 55 formed so as to insulate the transparent electrode layer 51a and the back electrode layer 54 of the electrode terminal portion d of the EL element has its own capacitance increased. As a result, the current consumption increases in order to prevent loss due to a, Yes formed by those dielectric constant than the insulating layer 53 is low, the light emitting layer 52 and the insulating layer 5
3 Further, the back electrode layer 54 is formed using a highly water-repellent fluororesin as a binder, and a sufficient moisture-proof effect is obtained without using a moisture-proof film.

The above-described thin and small-sized EL element is mounted on a small device such as a timepiece, and a power supply terminal 7 of the small device at that time is constituted by a coil spring or the like, and an electrode terminal d of the EL element is provided. Are electrically connected to each other (FIG. 3). This type of EL element is used for small devices
When mounting the device, specially pull out the electrode from the EL element and arrange
Electrical connection at the same time as assembly without wire connection
It is what is done.

[0005]

When an EL element is put into practical use, its specifications require durability and reliability under a high-temperature environment. In the above-described conventional EL element, the electric insulating resin layer is softened in a high temperature environment, and the power supply terminal of the small device is connected to the E terminal.
When connected to the electrode terminal of the L element at a desired pressure, the electrically insulating resin layer flows and short-circuits the transparent electrode layer and the back electrode layer (FIG. 3 shows a short-circuit state). (Shown). In practice, for example, 80
In a high-temperature environment of ° C, data has been obtained that the EL element having the conventional configuration causes a short circuit between the transparent electrode layer and the back electrode layer in about 24 hours. Did not.

Accordingly, an object of the present invention is to provide an EL element having excellent durability and reliability at high temperatures by providing an electrically insulating resin layer having excellent heat-resistant shape maintenance properties.

[0007]

According to the present invention, there is provided a transparent electrode film having a transparent electrode layer formed on a rear surface thereof, a light emitting layer formed on a rear surface of the transparent electrode film, In an EL element having an insulating layer formed on the back surface of the layer and a back electrode layer formed on the back surface of the insulating layer, the light emitting layer and the insulating layer are formed in the electrode terminal portion of the EL element.
The transparent electrode layer and the back surface outside the area where
Those are provided, et al is within a region where the electrode layer is formed
Yes, the electrically insulating resin layer, which is formed to insulate the transparent electrode layer and the back electrode layer to form one pole of the electrode terminal portion, has insulating heat-resistant powder dispersed in the electrically insulating resin. It is constituted by doing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the preferred embodiments shown in the accompanying drawings. As shown in FIG. 1, the transparent electrode film 1 is made of polyethylene terephthalate (PE).
The transparent conductive film is formed by depositing ITO constituting the transparent electrode layer 1a on the film T) to form a transparent conductive film. The light emitting layer 2 is formed by printing a light emitting ink on the upper surface of the transparent electrode film 1. Cu-doped zinc sulfide (ZnS) is used as a phosphor constituting the luminescent ink. A binder prepared by dissolving 60 g of this phosphor and 10 g of a copolymer of vinylidene fluoride and propylene hexafluoride in 25 g of methyl ethyl ketone as a fluororesin binder is mixed and stirred to produce a luminescent ink. The luminescent ink is printed on the ITO vapor-deposited surface by a method such as screen printing, and then heated and dried to form the luminescent layer 2.

Next, an insulating layer 3 is formed on the light emitting layer 2 by the same method as the formation of the light emitting layer 2. The insulating ink forming the insulating layer 3 is made by, for example, mixing and stirring 60 g of a high dielectric substance made of barium titanate (BaTiO ₃ ) and 35 g of the above-mentioned fluororesin binder.

[0010] The back electrode layer 4 is formed by printing carbon ink on the insulating layer 3, heating and drying. The back electrode layer 4 is formed one size smaller than the insulating layer 3. As an example, the carbon ink is formed by mixing carbon powder with polyester as a binder. In addition, the back electrode layer 4 may be composed of carbon powder, silver powder, copper powder, and polyester as a binder. The back electrode layer 4 is
In addition, the light emitting layer 2 may be made of a high dielectric substance and a fluororesin in order to provide a protection effect against intrusion of moisture into the light emitting layer 2.

In the electrode terminal portion D of the EL element, an electrically insulating resin layer 5 formed so as to insulate the transparent electrode layer 1 from the back electrode layer 4 is provided in order to prevent a loss in capacitance. Polyester having a lower dielectric constant than the insulating layer 3 of
Although it is formed by adopting vinyl chloride, urethane resin or acrylic, in the present invention, it is constituted by dispersing insulating heat-resistant powder 6 in electrically insulating resin layer 5. Heat resistance The powder 6 is made of melanin resin particles, titanium oxide (TiO 2).
₂ ), silicon oxide (SiO ₂ ), etc., whose particle size is 1
It is about μm. In this embodiment, the electrically insulating resin layer 5 is formed by adding titanium oxide to a polyester resin.

Here, the heat resistant powder 6 will be described. Effect of heat resistance by adding heat resistant powder 6
Although the addition of heat-resistant powder 6 on the electrically insulating resin layer 5 for enhancing the heat resistance powder 6 in order to obtain the effect of the heat resistance
Of 20 wt% or more is required . However, since the electrically insulating resin layer 5 is formed by screen printing,
The amount of heat-resistant powder 6 that can be screen printed is 80 wt.
% Or less. Therefore, the addition amount of the heat-resistant powder 6 is 2
The applicable range is 0 to 80 wt%, but the optimum value is 40 to 60 wt% in consideration of the heat resistance effect, printability, and the like.

FIG. 2 shows a state in which the EL element of this embodiment is mounted on a small device (not shown) such as a timepiece, and a power supply terminal 7 of the small device.
Indicates a state in which it is in elastic contact with and electrically connected to the electrode terminal portion 7 of the EL element.

In the state of FIG. 2, the amount of the insulating heat-resistant powder 6 added and the softening of the electrically insulating resin layer 5 cause EL.
Table 1 shows the results obtained by performing an acceleration test in a high-temperature (80 ° C.) environment with the time until the electrode terminal portion D of the element is short-circuited.
Shown in

[0015]

[Table 1]

In this embodiment, the silane coupling agent having a functional group capable of chemically bonding to both the inorganic material and the organic material, which are poorly compatible with each other, and bridging the interface between the inorganic and organic materials, is used to electrically insulate. The heat-resistant powder 6 dispersed in the conductive resin layer 5 and the electrically insulating resin are strongly chemically bonded, thereby further improving the effect of the present invention.

In Table 1, the addition amount of the heat-resistant powder 6 is 0.
In the EL element having the conventional configuration, the time required for the electrode terminal portion D of the EL element to be short-circuited is 24 hours.
On the other hand, the EL device of the present invention to which the heat-resistant powder 6 is added, for example, specifically has a heat resistance of 40% by weight of the resin.
A solvent is added to a dispersion in which the conductive powder 6 is dispersed at a ratio of 60 wt% to form a paste.
In the one formed by adding the t% silane coupling agent, the time until the electrode terminal portion D of the electrically insulating resin layer 5 of the EL element is short-circuited is extended to 1000 hours.

Here, the silane coupling agent will be described. The effect can be obtained by adding a silane coupling agent is 1 wt% or more, but 5 wt%.
If it becomes more than this, it will react with air and will harden, and a printability will worsen. Therefore, the optimum value of the added amount of the silane coupling agent is 2-3 wt%.

As described above, by adding the heat-resistant powder 6, the durability reliability of the EL element at high temperatures is improved.

[0020]

According to the constitution of the present invention, when the EL element is used at a high temperature, the time until the occurrence of the problem that the electrically insulating resin layer is softened and the electrode terminals are short-circuited is extended. As a result, it becomes possible to obtain an EL element having excellent durability reliability at high temperatures.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of an EL element of the present invention, wherein (a) is a plan view and (b) is a cross-sectional view.

FIG. 2 is a cross-sectional view showing a state in which a power supply terminal of the small device is elastically connected to an electrode terminal portion of the EL device when the EL device of the present invention is mounted on the small device and is electrically connected thereto.

FIG. 3 is a cross-sectional view illustrating a state in which a power supply terminal of a small device when the conventional EL device is mounted on the small device is electrically connected to an electrode terminal of the EL device by a method such as crimping.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Transparent conductive film 1a Transparent electrode layer 2 Light emitting layer 3 Insulating layer 4 Back electrode layer 5 Electrically insulating resin layer 6 Heat resistant powder D Electrode terminal part

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shigehiko Aoki 4-1-1, Taihei, Sumida-ku, Tokyo Inside Seikosha Co., Ltd. (56) References JP-A-61-51796 (JP, A) JP-A-63 -226894 (JP, A) JP-A-3-15192 (JP, A) JP-A-2-234391 (JP, A) JP-A-5-326152 (JP, A) (Japanese) Sho-62-84198 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H05B 33/06

Claims (1)

(57) [Claims] A transparent electrode film having a transparent electrode layer formed on a back surface thereof; a light emitting layer formed on a back surface of the transparent electrode film; an insulating layer formed on a back surface of the light emitting layer;
A back electrode layer formed on the back surface of the insulating layer.
In the L element, the electrode terminal portion of the EL element includes the light emitting layer and the insulating layer.
Outside the region where the layer is formed and the transparent electrode layer
And in the region where the back electrode layer is formed.
And form one pole of the electrode terminal portion.
In order for the transparent electrode layer and the back electrode layer to be insulated from each other, the electrically insulating resin layer is formed by dispersing an insulating heat-resistant powder in the electrically insulating resin. Characteristic EL element.