JPH03219590A - Distributed electroluminescence element - Google Patents

Abstract

PURPOSE:To prevent deterioration in an emission layer due to permeation of moisture by bending the outer circumference of the emission layer as well as that of a water- trap layer on the side of a transparent electrode, in the direction to the side of a back electrode, and covering the outer circumference of the emission layer with that of the water-trap layer. CONSTITUTION:A deposited layered body of a transparent electrode 1, an emission layer 4, a dielectric layer 5, and of a back electrode 6, is formed by applying the electrode 1 to the layer 4, in such a manner that it is superimposed on the layer 4 from the side of a transparent conductive film 3. An upper water-trap layer 7 is arranged on the upper surface of a transparent substrate 2 of the electrode 1, while a lower water-trap layer 9 is arranged on the under surface of the back electrode 6. An outer circumference 4a of the layer 4 is bent toward the side of the electrode 6, while that of the electrode 1 is also bent along this, and an outer circumference 7a of the layer 7 on the side of the electrode 1 is arranged outside of these, in such a manner that it is bent and directed toward the electrode 6, and an outer circumference 4a of the layer 4 is covered with an outer circumference 7a of the layer 7 on the side of the electrode 1. The moisture that permeates bonding agent layers 9a, 10a of water-proof films 9, 10 and intrudes into the element is thus disabled to reach the layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a distributed electroluminescent device.

[Conventional technology]

Conventional distributed electroluminescent elements are
As shown in Figure 7, a transparent electrode (1), a light-emitting layer (4), a dielectric layer (5), and a back electrode (6) are laminated, and a water-trapping layer is provided on the upper and lower surfaces of the laminated body. (7) and (8) are arranged, moisture-proof films (9) and (10) are arranged as exterior bodies on the upper and lower surfaces of the water-catching layers (7) and (8), and moisture-proof films (9) and 0 At the outer periphery of (I), the adhesive layer (9
a) and (10a) were bonded together, and the joints thereof were sealed. A lead terminal (10,0) for connecting this distributed electroluminescent element to an external power source (11) on the side of the transparent electrode (1) has one end connected to the lead terminal (11) as shown in FIG. It is connected to the transparent conductive film (3) of the transparent electrode (1), and the other end is pulled out from the side edge of the joint at the outer periphery of the moisture-proof films (9) and (10), and is connected to the back electrode (6) side. As shown in FIG. 7, the lead terminal 02) has one end connected to the back electrode (
6), and the other end is connected to the moisture-proof film (9), O
D) is pulled out from the side end of the joint at the outer periphery. And the moisture-proof films (9) and (10)
Generally, a trifluorochloroethylene resin film is laminated with low melting point plastic films such as polyethylene films as adhesive layers (9a) and (10a), and the joints are sealed by heating. A method was adopted in which the adhesive layers (9a) and (10a) were thermally fused (melted and bonded) (for example, in JP-A-60-2
No. 49293).

However, in such a distributed electroluminescent device, one of the water-trapping layers (7) is connected to the transparent electrode (
1) on the top surface of the transparent substrate (2), and the other water-trapping layer (
8) is only placed on the lower surface of the back electrode (6) of the laminate, therefore, in the direction of the upper and lower surfaces of the laminate, moisture that has passed through the moisture-proof films (9) and (10) is absorbed. Although the layers (7) and (8) can sufficiently capture water, in the side direction of the laminate, moisture-proof film (9), adhesive layers (9a), (10a) of O(D), etc. The water absorption layers (7) and (8) cannot sufficiently capture the water that has passed through, and as a result, the phosphor in the light emitting layer (4) reacts with the water and deteriorates, causing the dispersed electrolyte There was a problem that the life of the luminescent element was shortened.

Therefore, by changing the material of the exterior body or using a moisture-proof film that does not have a heat-fusible adhesive layer, moisture can be prevented from permeating into the element from the adhesive layers (9a) and (10a). However, moisture-proof films (9) and (10) having heat-fusible adhesive layers (9a) and (10a) as described above have been used as the exterior body of the dispersed electroluminescent element. The reason for this is that the above-mentioned moisture-proof film (9) and Q(D) have flexibility and can be easily sealed by heating, making it easy to manufacture a dispersed electroluminescent device. and its adhesive layer (9a)
Even though it is known that (10a) is made of a low-melting-point heat-fusible plastic such as polyethylene and has the disadvantage of being easily permeable to moisture, it is difficult to replace it with another material. was there.

[Problem to be solved by the invention]

As mentioned above, in the conventional dispersion type electroluminescent element, the present invention sufficiently absorbs the moisture that permeates from the side direction of the laminate, that is, the moisture that permeates through the adhesive layer at the joint of the moisture-proof film as an exterior body. This solves the problem that the life of the dispersed electroluminescent element was shortened due to the inability to capture water. It is an object of the present invention to provide a long-life dispersion type electroluminescent device whose light emitting layer is less likely to deteriorate due to moisture.

[Means to solve the problem]

In the present invention, the outer periphery of the light emitting layer is curved toward the back electrode side, and the outer periphery of the water trapping layer on the transparent electrode side is curved toward the back electrode side, and the outer periphery of the water trapping layer on the transparent electrode side is curved. The above objective is achieved by covering the outer periphery of the light emitting layer with the light emitting layer.

That is, as described above, the outer circumference of the light-emitting layer is curved toward the back electrode side, and the outer circumference of the water-trapping layer on the transparent electrode side is curved toward the back electrode side, so that the water-trapping layer on the transparent electrode side is curved. By covering the outer periphery of the light-emitting layer with the outer periphery of the transparent electrode, moisture that has penetrated the adhesive layer of the moisture-proof film and entered the element is captured by the outer periphery of the water-catching layer on the transparent electrode side and is absorbed into the light-emitting layer. As a result, deterioration of the light-emitting layer due to moisture from the side surfaces of the laminate is suppressed, and the dispersion type electroluminescent device can be used for a long time, achieving a longer lifespan.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

1 to 3 show an embodiment of the dispersion type electroluminescent device of the present invention, and FIG. 1 is an enlarged vertical sectional view thereof, which corresponds to the sectional view taken along the line A-A in FIG. 3. be. FIG. 2 is an enlarged longitudinal cross-sectional view of the dispersion type electroluminescent element in a cross section orthogonal to the first cross section, and corresponds to the cross-sectional view taken along the line B--B in FIG. 3. FIG. 3 is a schematic plan view of a distributed electroluminescent device.

In the figure, (1) is a transparent electrode, and this transparent electrode (1) is attached to one surface of a transparent substrate (2) made of a polyethylene terephthalate film with a thickness of 75 μm.
(1 (100 people)) A transparent conductive film (3) of ITO (indium tin oxide) was formed.

(4) is a light emitting layer, (5) is a dielectric layer, and (6) is a back electrode. This back electrode (6) has a thickness of 11 (10
The dielectric layer (5) is made of 1I aluminum foil, and the dielectric layer (5) is coated with high dielectric powder such as barium titanate or titanium oxide, cyanoethylated pullulan, cyanoethylated cellulose, or hydroxycyanoethylated cellulose on the back electrode (6). A paste for forming a dielectric layer mainly consisting of an organic binder such as cyanethylated polyvinyl alcohol was applied and dried to a thickness of 60 μm. The light emitting layer (4) is made of ZnS on this dielectric layer (5).
: A paste for forming a light emitting layer mainly consisting of a phosphor such as Cu or C1 and the same organic binder as above was applied and dried to a thickness of 1 (10 μm).

The transparent electrode (1) is placed on this light emitting layer (4) for its transparent conductivity It! A laminate of the transparent electrode (1), the light-emitting layer (4), the dielectric layer (5), and the back electrode (6) is formed by overlapping and pressing from the <3+ side.

(7) and (8) are water-catching layers each made of a nylon 6 film with a thickness of 120 μm, and the water-catching layer (7) is formed on the top surface of the transparent substrate (2) of the transparent electrode (1) of the laminate. The water trapping layer (8) is placed on the lower surface of the back electrode (6) of the laminate.

The outer periphery (4a) of the light-emitting layer (4) is curved toward the back electrode (6), and the outer periphery of the transparent electrode (1) is also curved along it. ) side of the water-trapping layer (7) is arranged in a curved state with the outer circumference (7a) facing the back electrode (6) side.
a) is the outer periphery (7a) of the water-trapping layer (7) on the transparent electrode (1) side.
) is covered.

(9) and (10 are moisture-proof films as exterior bodies made of trifluorochloroethylene resin film as a base material, and these moisture-proof films (9) and 0ffl each have a low-temperature film such as polyethylene on one side. An adhesive layer (9a) formed by laminating a film of melting point resin, (
10a), and one moisture-proof film (9) has a water-trapping layer (
7), and the other moisture-proof film 0 (1) is placed on the bottom surface of the water-trapping layer (8).
), (10) has an adhesive layer (9a) on its outer periphery.
, (10a) are bonded together by heating with a press or the like, and their joints are sealed.

(11) in Fig. 3 is the lead terminal on the transparent electrode (1) side, and the lead terminal (l 1) on the transparent electrode (1) side.
In FIG. 1, the outer periphery of the light emitting layer (4) (
The mounting state is not shown because it would be difficult to see the bending state of 4a) toward the back electrode (6) side.
Similar to the conventional dispersion type electroluminescent device shown in FIG. 6, one end of the device is connected to a transparent electrode (
It is attached to the transparent conductive film (3) of 1), and the other end is pulled out from the side end of the junction of the moisture-proof film (9) and 0ffl.

In addition, (+21 in FIG. 3 is the lead terminal on the back electrode (6) side, and lead terminal 02 on the back electrode (6) side.
) is similar to the case of the lead terminal 01) on the transparent electrode (1) side described above, and its mounting state is not shown in FIG. 1, but it is similar to the conventional dispersion type electroluminescent element shown in FIG. One end of the laminate is attached to the lower surface of the back electrode (6) (that is, the surface on which the dielectric layer (5) is not formed) when forming the laminate, and the other end is attached to the moisture-proof film (
9), 0(0) is pulled out from the side edge of the joint.

In the present invention, the method of curving the outer peripheral part (4a) of the light emitting M (4) toward the back electrode (6) is not particularly limited;
A light emitting layer (4) - dielectric layer (5) - with a dielectric layer (5) formed thereon and a light emitting layer (4) formed on the dielectric layer (5)
A punching jig C! in which a three-layer laminate consisting of a back electrode (6) is arranged with the light-emitting layer (4) facing upward as shown in FIG. 4, and the inner peripheral surface is curved from above. ■The punching method is adopted. When punched using the punching jig QΦ as described above, the outer peripheral part (4a
) is pushed toward the back electrode (6) (accompanyingly, the outer periphery (5a) of the dielectric layer (5) is also pushed toward the back electrode (6)), and the outer periphery (4a) of the light emitting layer (4) becomes curved toward the back electrode (6). In order to cover the outer periphery (4a) of the light-emitting layer (4) with the outer periphery (7a) of the water-trapping layer (7) on the side of the transparent electrode (1), the outer periphery of the light-emitting layer (4) is (4a) is curved toward the back electrode (6) side, and the transparent electrode (1) is overlaid and pressure-bonded from the transparent conductive film (3) side on top of it, forming a water-trapping layer (7).
, (8) and the moisture-proof films (9), (10) are placed at predetermined positions, and the outer periphery of the water-trapping layer (7) is The portion (7a) is curved toward the back electrode (6) side together with the outer circumferential portion of the transparent electrode (1), thereby causing the outer circumferential portion (7a) of the water-trapping layer (7) on the transparent electrode (1) side to emit light. layer(
4) to cover the outer periphery (4a).

In this example, the dimensions for curving the outer peripheral part (4a) of the light-emitting layer (4) toward the back electrode (6) are those of the transparent electrode (1).
The thickness is twice the thickness of the laminate of the laminate and the light-emitting layer (4), but generally the thickness is twice the thickness t of the laminate (2t).
) is preferably within the range. In other words, if the curved dimension is smaller than the above range, the water-trapping layer on the transparent electrode (1) side (the outer circumference of the light-emitting layer (4) (7a) and the outer circumference of the light-emitting layer (4) (
4a) becomes difficult to cover, reducing the moisture-proofing effect, and if it exceeds the above range, the transparent electrode (1) and the back electrode (6) may come into contact and short circuit may occur. .

As shown in the above embodiments, the distributed electroluminescent device of the present invention has the outer circumference (4a) of the light emitting layer (4) curved toward the back electrode (6), and the transparent electrode (1
) side of the water trapping layer (7) as the back electrode (6).
The outer circumference (4a) of the light-emitting layer (4) is curved toward the side, and the outer circumference (7a) of the water-trapping layer 1 (7) on the side of the transparent electrode (1) is connected to the outer circumference (4a) of the light-emitting layer (4).
) by covering the moisture-proof film (9), (10)
Water that has penetrated into the device through the adhesive layers (9a) and (10a) is removed by the water-catching layer (on the transparent electrode (1) side).
Water is captured by the outer peripheral part (7a) of 7), and the light emitting layer (4)
Prevents moisture from reaching the Therefore, compared to conventional dispersion type electroluminescent elements, the light-emitting layer (4) is less degraded by permeated moisture and can be used for a long time, resulting in a so-called long life.

Table 1 below compares the luminance half-life of the dispersion type electroluminescence device of the present invention shown in the above example and the conventional dispersion type electroluminescence device shown in FIGS. 6 and 7.

To measure the luminance half-life, both electroluminescent elements were incubated at 20°C and 65% relative humidity.
4 (This was done by applying an AC voltage of 10 Hz and measuring the driving time until the luminance decreased to 1/2 of the initial luminance. Both electroluminescent elements were of the present invention. , the outer peripheral part of the light emitting layer (4) (
4a) toward the back electrode (]) side, and curve the outer periphery (
7a) covers the outer periphery (4a) of the light-emitting layer (4), whereas in the conventional one, the outer periphery (4a) of the light-emitting layer (4) is curved and the water-trapping layer (7) The only difference is that the outer periphery (4a) of the light emitting layer (4) is not covered by the outer periphery (7a) of the light-emitting layer (4), and the other configurations are almost the same.

Table 1 As shown in Table 1, the dispersion type electroluminescence device of the present invention has a larger luminance half-life and a longer period than the conventional dispersion type electroluminescence device (shown as conventional product in Table 1). It can be used for many hours and has a long lifespan.

The materials and dimensions of each component of the dispersion type electroluminescent device shown in the above examples are shown only for the examples, and materials and dimensions different from those exemplified in the examples may not be used. Of course, it is also possible to use

[Effects of the Invention] As explained above, in the present invention, the outer peripheral part (4a) of the light emitting layer (4) is curved toward the back electrode (6) side, and the water-trapping layer on the transparent electrode (1) side is curved. The outer peripheral part (7a) of (7) is curved toward the back electrode (6) side, and the transparent electrode (1)
By covering the outer periphery (4a) of the luminescent layer (4) with the outer periphery (7a) of the side water-catching layer (7), the moisture-proof film (9)
, (10), the moisture that has passed through the adhesive layers (9a) and (10a) is captured by the outer periphery (7a) of the water-catching layer (7), thereby reducing the luminescent layer (4) due to the transmitted moisture. It was possible to provide a long-life distributed electroluminescent element with little deterioration.

[Brief explanation of drawings]

1 to 3 show an embodiment of the dispersion type electroluminescent device of the present invention, and FIG. 1 is an enlarged longitudinal sectional view thereof, which corresponds to the sectional view taken along the line I-A in FIG. 3. There is, and Figure 2 is an enlarged longitudinal sectional view taken at a cross section perpendicular to Figure 1.
4 is a diagram corresponding to a sectional view taken along line B-B in FIG. 3. FIG. FIG. 3 is a schematic plan view of a distributed electroluminescent device. FIG. 4 is a sectional view showing a state in which a three-layer laminate consisting of a light emitting layer, a dielectric layer and a back electrode is punched out using a punching jig in an embodiment of the present invention, and FIG. FIG. 2 is a cross-sectional view of a three-layer laminate consisting of a light-emitting layer, a dielectric layer, and a back electrode, punched out using a punching jig. 6 and 7 show a conventional dispersion type electroluminescent device, with FIG. 6 being an enlarged longitudinal sectional view thereof, and FIG. 7 being an enlarged longitudinal sectional view taken in a cross section parallel to FIG. 6.

Claims (1)

[Claims] 1. A transparent electrode (1), a light emitting layer (4), and a dielectric layer (
5), a back electrode (6), a water trapping layer (7), (8),
The transparent electrode (1) has a transparent substrate (2) and a transparent conductive film (3), and the moisture-proof films (9) and (10) have moisture-proof films (9) and (10). Each has adhesive layers (9a) and (10a) on one side, and the transparent electrode (1), the light emitting layer (4), the dielectric layer (5), and the back electrode (6) are laminated. The water-trapping layer (7) comprises a transparent substrate (1) of the transparent electrode (1).
The water-trapping layer (8) is placed on the bottom surface of the back electrode (6), and the moisture-proof films (9) and (10) are placed on the top surface of the water-trapping layer (7), respectively. , (8), and the moisture-proof films (9), (10) are bonded with adhesive layers (9a), (10a) at their outer peripheries, thereby forming a joint between the moisture-proof films (9), (10). In the dispersion type electroluminescence device, the outer peripheral part (4a) of the light-emitting layer (4) is curved toward the back electrode (6) side, and the water-trapping layer on the transparent electrode (1) side is curved. (7) Outer periphery (7a)
The outer peripheral part (7a) of the water-trapping layer (7) on the transparent electrode (1) side is curved toward the back electrode (6) side.
A dispersion type electroluminescent device, characterized in that an outer peripheral portion (4a) of a light emitting layer (4) is covered with a light emitting layer (4).