JPS62177893A - Manufacture of el panel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the production of an EL panel using an EL element and injecting and sealing an insulating protective material to protect the EL element from moisture etc. Regarding the method.

[Conventional technology]

Generally, there are two types of EL elements: thin film type and thick film type. Among these, thin-film EL devices are made by closely forming a transparent electrode made of a transparent conductive material such as In or O on a transparent substrate such as glass using an appropriate method such as vapor deposition or sputtering. A first dielectric layer made of an insulating material such as Y2O3 to prevent this, a light-emitting layer made of a matrix material such as ZnS doped with a luminescent center such as Mn, and the first dielectric layer above that. a second dielectric layer made of the same material as above, and a second dielectric layer 11 thereon as an electrode facing the transparent electrode and having reflective properties.
The back electrode made of a conductive material such as No. 4 is sequentially laminated using an appropriate method such as vapor deposition or sputtering. An EL element with such a structure has a first or a second
Moisture or the like enters the light-emitting layer through defects such as pinholes and microcranks generated during the manufacturing process of the dielectric layer, resulting in heat generation due to EL light emission loss, delamination, and deterioration of light-emitting characteristics. For this reason, thin-film EL panels that generally use EL elements are manufactured under the Japanese Patent Publication No. 57-4755.
As disclosed in Japanese Patent Application No. 9, the transparent substrate and the back plate facing the substrate constitute an envelope for housing the EL element, and therein is an insulating protective envelope that blocks the EL element from moisture and the like. Some types seal the envelope by injecting a fluid (such as silicone oil).

[Problem that the invention seeks to solve]

However, this injected and sealed fluid may expand due to thermal changes, and the expanded liquid may leak from the bonded area between the transparent substrate and the back plate or from the area sealed with adhesive after the fluid is injected. There is. A system designed to reliably store such leaked liquid was developed in 1986-215.
It is disclosed in Publication No. 7. This has a double-sealed structure in which the fluid injection part on the outside of the envelope is covered with a glass camp, and the fluid that leaks out by breaking the adhesive on the fluid injection part is stored in this camp.

However, although this cap is about 3-3cm thick, it is easily destroyed because it protrudes from the flat back plate, and the expanded fluid does not necessarily leak from the object injection point and be stored in the cap. However, the reliability is low because it may leak to the outside of the envelope from other bonded parts. Further, the double sealing structure in which a small glass cap is again placed on the outside of the envelope has the problem that the work is complicated and the EL panel becomes expensive.

Problems caused by moisture similarly occur when constructing an EL panel made of thick film EL elements.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention constitutes an envelope for housing the EL element by fixing a back plate provided with an injection tube to a transparent substrate on which the EL element is mounted, and gelling the EL element. injecting an insulative protective material for the EL element containing an agent into the envelope through the injection tube, gelling the insulating protective material injected into the envelope, and then sealing the injection tube. It is characterized by:

[Effect]

The insulating protective material is gelled by applying heat or irradiated with ultraviolet rays, and this gelled insulating protective material has a smaller coefficient of thermal expansion than liquid materials, so it can be used even at high temperatures. It is possible to prevent the envelope from being destroyed due to internal thermal expansion.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings. The embodiment uses a thin film EL device, and in FIG. 1, the thin film EL device is constructed by a conventional method. That is, the EL element 1 is manufactured by using a suitable method such as vapor deposition or sputtering on a transparent substrate 2 such as glass, and a transparent electrode 3 made of a transparent conductive material such as In2O2. A first dielectric layer 4 made of an insulating material such as . A second dielectric layer 6 made of the same material as above, and a back electrode 7 made of a conductive material such as AA as a reflective electrode facing the transparent electrode 3 are sequentially formed on the second dielectric layer 6 by a suitable method such as vapor deposition or sputtering. It is formed by laminating layers using a method.

(First step) In order to hermetically seal this EL element 1, a transparent substrate 2, which is one of the components of the EL element 1, is covered with a layer having a thickness of 0.5 to 1, surrounding the side surface of the EL element 1. A spacer 8 having a width of about 1 to 5 mm is placed and bonded with an epoxy adhesive 9. Next, a minute injection hole 10 is made with a drill etc., an aluminum injection pipe 11 is inserted into this injection hole 10, and the thickness 21 is bonded with the silicone adhesive side 9A, which has a weak adhesive force.
A back plate 12 made of a flat plate member such as glass having a diameter of about 1.5 m is placed on the spacer 8 and the lid is closed, and the spacer 8 and the back plate are bonded together with an epoxy adhesive 9. These transparent substrates2. The spacer 8 and the back plate 12 constitute an envelope 13 that hermetically seals the EL element 1, and the mating portion around the envelope 13 is sealed with an adhesive 9 to ensure airtightness. Note that the envelope 13 may be formed by polishing the center portion of the back plate 12 having a thickness of about 3 fi to form a concave portion large enough to accommodate the EL element 1, without using the spacer 8. In addition, as the envelope 13, the injection pipe 11
The back plate 12 and the back plate 12 may be integrally formed of resin.

(Second Step) The envelope 13 containing the EL element 1 is placed in a vacuum device 14 as shown in FIG. A fluid storage tank 15 in the vacuum device 14 contains a moisture blocking agent 16 made of a material such as silicone that has the effect of blocking the EL element 1 from moisture, etc., and a moisture blocking agent 16 made of a material that has a moisture absorbing effect such as molecular sieves powder. It is filled with an insulating protective material 19 composed of an absorbent 17 and a gelling agent 18 such as silicone which is gelled by heating. Then, after reducing the pressure in the vacuum device 14 and degassing the EL element 1 and the insulating protective material 19, the tip of the injection tube 11 is inserted into the insulating protective material 19 as shown in the figure while maintaining the vacuum state. . After that, nitrogen gas is injected from the valve 20 of the vacuum device 14 and the vacuum device 1
When the pressure inside the container 4 is returned to atmospheric pressure, the insulating protective material 19 is injected into the envelope 13 through the injection pipe 11 due to the atmospheric pressure.

This nitrogen gas is used because it is relatively easy to prevent moisture from entering the vacuum device 14, but other gases may also be used.

(Third Step) The envelope 13 filled with the insulating protective material 19 is placed in the heating device 21 as shown in FIG. This heating device 21
Since the inner diameter of the injection tube 11 is relatively small, there is little risk that the insulating protective material 19 will leak out due to capillary action. And, as shown in Figure 5,
The temperature of the heating device 21 is raised (to to L1) and maintained at a high temperature (1+ to tz). At this high temperature, the gelling agent 18 in the envelope 13 is gelled, and therefore the insulating protective material 19
is gelled.

(Fourth step) After the insulating protective material 19 is gelled as shown in FIG. After removal such as pulling out or cutting, the injection hole 10 is sealed with a heat-curable silicone adhesive 9A and kept at a high temperature (tz~t
3) Cure the adhesive 9A. After the adhesive 9A is cured, the heating device 21 is cooled (t, to t4), and the epoxy adhesive 9 is applied on the adhesive 9A on the injection hole 10 for reinforcement, and the silicone adhesive 9A is The temperature is maintained at a temperature lower than the curing temperature (t4 to ts) to cure the adhesive 9 and complete sealing of the injection hole 10. Then, the heating device 21 is cooled down to room temperature (js-j6), and the EL panel is completed.

The EL panel manufactured through the above steps has an envelope 13
Since the insulating protective material 19 inside is gelled by the gelling agent 18, even if the EL panel is operated at high temperature or left at high temperature (approximately 100°C), the gelled insulating protective material 19 will not be removed. Due to its vapor nature and low coefficient of thermal expansion,
Since the increase in the internal pressure of the hermetically sealed envelope 13 is smaller than that of conventional liquid protective fluids, it is possible to prevent the envelope 13 from being destroyed at its adhesive points and the protective fluid leaking out. It can be prevented. In addition, the injection hole 10 is sealed by the heating device 2.
1, moisture does not infiltrate into the envelope 13 during this sealing, and since the injection tube 11 has a small diameter, there is almost no leakage of the insulating protective material 19. Since there is no need to crush it for temporary sealing, the injection tube 11 may be made of metal or resin. Furthermore, the injection tube 11 is in a state where the insulating protection material 19 is gelled.
, the injection tube 11 can be pulled out or cut into shorter pieces, making it easier to process.
The portion of the sealing portion of the injection hole 10 that protrudes from the envelope 13 is minimized.

In addition, since the hardness of gelling can be adjusted by increasing or decreasing the amount of gelling agent 18, surface tension or stress that is a burden on the EL element 1 is not applied, and the moisture blocking agent 16 is impregnated into the insulating protective material 19. Therefore, it has permeability to pinholes in the dielectric layer, and prevents E from moisture entering into the envelope 13.
Protect L element 1.

Although one embodiment of the present invention has been described in detail above, it can be modified as appropriate within the scope of the gist of the present invention. For example, in the above embodiment, the insulating protective material 19 was gelled by heating, but the gelling agent 1
As shown in FIG. 2, an insulating protective material 19 is injected into the envelope 13, and then the envelope 13 is irradiated with ultraviolet rays to crosslink the ultraviolet curable silicone. In this way, the insulating protective material 19 can also be turned into a gel. In this case, since irradiation with ultraviolet rays only takes several seconds to several minutes, an EL panel can be manufactured in a shorter time than the thermosetting type, which requires tens of minutes to several hours. Further, although the above embodiments have shown thin film EL elements, the present invention can be similarly applied to EL panels using thick film EL elements.

〔Effect of the invention〕

As described in detail above, according to the present invention, a back plate provided with an injection tube is fixed to a transparent substrate on which an EL element is mounted to constitute an envelope for housing the EL element, and gelling is performed. injecting an insulative protective material for the EL element containing an agent into the envelope through the injection tube, gelling the insulating protective material injected into the envelope, and then sealing the injection tube. This makes the coefficient of thermal expansion of the gelled insulating protective material inside the envelope smaller than that of the liquid material, preventing the envelope from being destroyed by internal thermal expansion under high temperatures and preventing fluid from leaking to the outside. This increases sealing reliability. Incidentally, FIG. 1 shows a structure in which an insulating protective material 19 is injected.

[Brief explanation of drawings]

Figures 1 to 4 show the manufacturing process of the present invention.
The figure is a sectional view of the EL panel, FIGS. 2 to 4 are front views showing the manufacturing process of the panel, and FIG. 5 is a time chart showing the temperature inside the heating device. 1...-EL element 2--Transparent substrate 9--Epoxy adhesive 10--Injection hole 11-Injection tube
12... Back plate 13-... Envelope 1
4-Vacuum device 16-Moisture blocking agent 17-Moisture absorbing agent 18--Gelling agent 19--Protective fluid 21--Heating device

Claims (1)

[Claims] A back plate provided with an injection tube is fixed to a transparent substrate on which an EL element is mounted to constitute an envelope for housing the EL element, and an insulating protective material for the EL element containing a gelling agent is provided. A method for producing an EL panel, comprising: injecting the insulating protective material into the envelope through the injection tube, gelling the insulating protection material injected into the envelope, and then sealing the injection tube.