JPH0115117Y2 - - Google Patents

Description

[Detailed explanation of the invention] Industrial application field This invention relates to glass package cage type EL.
It is particularly suitable for improving the contrast of a liquid crystal display device, which is a light-receiving type display device, or as a backlight for nighttime display.

2. Description of the Related Art Organic EL is preferred for backlights in liquid crystal display devices and the like because of its thinness, uniform brightness, and light weight. As this type of EL, for example, as disclosed in Japanese Patent Publication No. 36-8479, EL
There is a device in which the element is sandwiched between resin outer films and bonded under heat, but this has the disadvantage of poor moisture resistance. Therefore, as disclosed in Japanese Patent Publication No. 40-8575, an EL has been proposed in which moisture-absorbing films are disposed above and below an EL element, sandwiched between resin outer films, and bonded under heat to improve moisture resistance. however,
Even with such EL, moisture resistance was still insufficient. This is because the resin outer film inherently has moisture permeability, and as long as the resin outer film is used, there is a limit to the improvement in moisture resistance.

Therefore, the present applicant first developed a glass package cage type using a glass plate instead of a resin outer film.
I proposed EL. FIG. 5 shows a plan view of such a glass package type EL, and FIG. 6 shows an enlarged cross-sectional view of the main part taken along the - line in FIG. In the figure, 1 is a transparent first glass plate, and one main surface thereof is
A transparent electrode 2 made of ITO or the like is formed.
3 is a laminate consisting of a light-emitting layer 4, a reflective insulating layer 5, and a back electrode 6. For example, on the back electrode 6 made of aluminum foil, a high dielectric material such as barium titanate is placed in an organic material with a high dielectric constant such as cyanoethyl cellulose. A reflective insulating layer 5 is formed by coating a dispersion of white fine powder with a dielectric constant, and on top of that a dispersion of phosphor powder such as ZnS; Cu in an organic material similar to the above is coated to emit light. Layer 4 was formed. The surface of this laminate 3 on the light emitting layer 4 side is pressed onto the transparent electrode 2. 7 is a second glass plate, and the back electrode 6
is covered. Reference numerals 8 and 9 denote leads made of phosphor bronze thin plates or the like and electrically connected to the transparent electrode 2 and the back electrode 6, respectively. 10 is the first,
A sealing resin made of epoxy resin or the like is filled and sealed in the peripheral area between the second glass plates 1 and 7.

According to the above configuration, the first and second glass plates 1 and 7, which are not moisture permeable, are used for sealing instead of the resin outer film, and compared to the conventional EL sealed with a resin outer film. As a result, moisture resistance can be significantly improved. Moreover, the first glass plate 1 has a much higher transparency than a resin outer film, a moisture absorption film, a polyester film that is the base material of the transparent electrode, etc., and the transparent electrode 2 itself is made of polyester. Because it can withstand much higher temperatures than film, it can be formed at much higher temperatures than conventional transparent electrodes, resulting in significantly higher transparency. Therefore, even if the luminance of the luminescent layer 4 itself is the same as that of the conventional one, the luminance of the EL will be lower than that of the conventional one due to less absorption and attenuation of light by the transparent electrode 2 and the first glass plate 1. It has the advantage of being significantly more expensive than

Problems to be solved by the invention By the way, in the above EL, the laminate 3 of the light emitting layer 4, the reflective insulating layer 5 and the back electrode 6 is placed on the first glass plate 1 on which the transparent electrode 2 is formed as described above. In the case of pressure bonding, as shown in FIG. The material is crimped by applying pressure, or by heating together with pressure. At this time, as shown by the solid line, when the laminator 11 bites the object to be crimped, and as shown by the two-dot chain line, when the laminator 11 releases the object to be crimped, the front end 3a and the rear end 3 of the laminate 3
b is greatly compressed and deformed. Therefore, as shown in FIG. 8, a problem occurs in that the distance g between the transparent electrode 2 and the back electrode 6 becomes small, and the withstand voltage and/or insulation resistance between them becomes small.

Means for Solving the Problems This invention is characterized in that an insulating layer is interposed between the transparent electrode and the peripheral edge of the light emitting layer.

Effect According to the above configuration, the laminate of the light emitting layer and the back electrode is crimped onto the transparent electrode of the first glass plate with the insulating layer interposed, so even if the laminate is crimped with a laminator as in the past, The transparent electrode and the back electrode are prevented from coming very close to each other as in the prior art, and a glass package type EL with high withstand voltage and/or high insulation resistance can be obtained.

Embodiment FIG. 2 shows an enlarged sectional view of essential parts of a glass package type EL according to a first embodiment of this invention. The figure is the same as FIG. 6 except for the following points, so the same parts are given the same reference numerals and the explanation thereof will be omitted. The difference from Fig. 6 is that the transparent electrode 2
An insulating layer 12 such as a polyester film is interposed between the light emitting layer 4 and the peripheral edge of the light emitting layer 4. The above insulating layer 12 is made of transparent electrode 2 in advance.
Paste a polyester film on top,
The laminate 3 may be placed on top of it and crimped, or
It may be pasted on the periphery of the light-emitting layer 4 and then pressure-bonded to the transparent electrode 2.

In any case, when the laminate 3 is placed on the transparent electrode 2 with the insulating layer 12 interposed, the peripheral part of the laminate 3 is slightly higher than the central part, as shown in FIG. There is. However, after passing this through the laminator, the sagging part at the peripheral edge compared to Fig. 8 is
As a result of being lifted up by the insulating layer 12, as shown in FIG. 4, the difference in level between the periphery and the center of the laminate 3 becomes significantly smaller and becomes almost flat. Therefore, unlike the conventional case, the distance between the transparent electrode 2 and the back electrode 6 does not become small, and the glass package type has a high withstand voltage and/or insulation resistance.
EL is obtained.

By the way, as mentioned above, when the insulating layer 12 is formed of a material different from the sealing resin 10, the effective sealing interface dimension l is generally poor due to poor adhesion between the resin 10 and the insulating layer 12. As a result, the moisture resistance tends to be low compared to the width L of the resin 10.

FIG. 1 shows an enlarged sectional view of a main part of a glass package type EL according to a second embodiment of the invention, which solves the above-mentioned problems. This embodiment is different from the embodiment shown in FIG.
The transparent electrode 2 is formed by applying the same epoxy resin as 0 on the transparent electrode 2. According to the above configuration, the insulating layer 13 has good adhesion to the transparent electrode 2 and the resin 10, and the width L of the resin 10 is entirely equal to the effective sealing interface length, improving moisture resistance. In other words, if the moisture resistance is the same, the dimensions of the laminate 3 can be increased to increase the light emitting area.

Effects of the Invention As described above, in this invention, since an insulating layer is interposed between the transparent electrode and the peripheral end of the light emitting layer, a glass package type EL with high withstand voltage and/or high insulation resistance can be obtained.

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part of a glass package type EL according to an embodiment of this invention. Fig. 2 is an enlarged cross-sectional view of the essential parts of a glass package type EL according to another embodiment of this invention, and Figs. 3 and 4 show different methods for crimping the first glass plate and the laminate. It is an enlarged sectional view of the main part of a stage. Fig. 5 is a plan view of a conventional glass package type EL, Fig. 6 is an enlarged sectional view of the main part taken along the - line in Fig. 5, and Figs. 7 and 8 explain the problems of the above EL. FIG. 4 is an enlarged cross-sectional view of a main part at different stages of a method of press-bonding a first glass plate and a laminate for the purpose of bonding the first glass plate and the laminate; DESCRIPTION OF SYMBOLS 1...First glass plate, 2...Transparent electrode, 3...
...Laminated body, 4...Light emitting layer, 6...Back electrode, 7...
... second glass plate, 10 ... sealing resin, 12,
13...Insulating layer.

Claims (1)

[Claims for Utility Model Registration] 1. A first glass plate on which a transparent electrode is formed, and a second glass plate formed with a transparent electrode.
A laminate of a light emitting layer and a back electrode is sandwiched between the first and second glass plates, and the peripheral edge between the first and second glass plates is hermetically sealed with a sealing resin, wherein the transparent electrode and A glass package type EL characterized by having an insulating layer interposed between the peripheral edge of the light emitting layer. 2. The glass package type EL according to claim 1, wherein the insulating layer is made of the same material as the sealing resin. 3. The glass package type EL according to claim 2, wherein the insulating layer and the sealing resin are made of epoxy resin.