JPH07105271B2 - Method of sealing protective liquid for thin film EL panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a method for encapsulating a protective liquid for a thin film EL panel using an AC electric field type thin film EL element.

<Prior Art> A conventional AC electric field type thin film EL panel is configured as shown in FIGS. 5 and 6.

That is, in the thin film EL panel shown in FIG. 5, a large number of parallel strip-shaped transparent electrodes 2 made of In ₂ O ₂ or SnO ₂ or the like are provided on the glass substrate 1, and Y electrodes are further provided on the transparent electrode 2. ₂ O ₃ , TiO ₂ , Al
The first dielectric layer 13 selected from any of ₂ O ₃ , Si ₃ N ₄ and SiO _2.
Is formed by a sputtering method, an electron beam evaporation method, or the like, and the ZnS light emitting layer 14 formed by depositing Zn: Mn sintered pellets on the upper surface of the first dielectric layer 13 by an electron beam evaporation method is covered. A second dielectric layer 15 made of the same material as the first dielectric layer 13 is formed. And the second dielectric layer
A large number of parallel strip-shaped back electrodes 16 made of Al are formed on 15 by vapor deposition in a direction intersecting with the transparent electrode 2.
AC power supply 17 is connected between and to drive. The thin film EL panel is widely used for displaying characters, symbols, various images, etc. as a flat and thin display device that takes advantage of the space factor, but in this case, the first and second Dielectric layer 13,1
5 includes a large number of pinholes, microcracks, etc. generated when laminating the light emitting layer 14 by 5, and moisture easily enters the light emitting layer 14 through these defective portions, which causes heat generation or interlayer due to EL light emission loss. There is a defect that peeling and other deterioration of element characteristics are caused.

Therefore, as a means for coping with the above-mentioned defects, there is one shown in FIG.

That is, FIG. 6 shows that a large number of parallel strip-shaped transparent electrodes 2 are formed on a glass substrate 1, and a first dielectric layer 13, a ZnS light emitting layer 14, and Si ₃ N ₄ are formed on the transparent electrodes 2. A film and a second dielectric layer 15 composed of an Al ₂ O ₃ film are sequentially laminated and formed, and a large number of parallel strip-shaped back electrodes 16 are crossed with the transparent electrode 2 on the dielectric layer 15. It is provided in the direction.

Then, a spacer 18 is provided on the transparent electrode 2 so as to surround the first dielectric layer 13, the light emitting layer 14, the second dielectric layer 15 and the back electrode 16, and the back glass plate 3a is bonded thereon. A space 4a is formed by the transparent electrode 2, the spacer 18, and the back glass plate 3a by adhering with the agent 19, and silicon is injected from one or a plurality of injection holes 5 formed in the back glass plate 3a in the space 4a. After filling a fluid (infiltration liquid) such as oil or grease, a flat glass cap 11 is attached to the outside of the injection hole 5 via a resin adhesive 9 such as an ultraviolet effect resin or an epoxy resin to form the injection hole. By encapsulating, the injection fluid aims to solve the problems caused by pinholes and microcracks.

<Problems to be Solved by the Invention> However, when injecting an injection hole with a flat glass cap,
When the adhesive 9 made of an ultraviolet curable resin is used, the workability is good, but since the moisture permeability coefficient is larger than that of the epoxy resin, moisture easily penetrates into the thin film EL layer and the reliability is lowered.

Further, when the adhesive 9 is an epoxy resin, the moisture permeability coefficient is small and the reliability is high, but the viscosity sharply decreases during the curing reaction and the fluidity is increased, so that the work jig of the EL panel is inclined even slightly. If so, the flat glass cap is displaced to cause a position defect. Therefore, in order to eliminate such a position defect of the cap, it is necessary to control the levelness of the working jig, which causes a cost increase.

The present invention aims to solve the above-mentioned drawbacks, reduce the occurrence of defective products during work, and provide a product with stable performance.

<Means for Solving the Problems> The method for sealing a thin film EL panel with a protective liquid according to the present invention is designed such that an EL layer is formed in a space surrounded by a transparent electrode on a glass substrate and a rear glass plate.
While holding the element, in a thin film EL panel formed by injecting a wetting liquid as a protective liquid from an injection hole provided in the back glass plate, the injection hole of the wetting liquid is sealed with an adhesive, and then the When sealing with an adhesive with a low moisture permeability that covers the adhesive and a glass cap that is adhered to the back glass plate by this adhesive, the glass cap is temporarily placed on the back glass plate with a fast-curing adhesive. It is characterized by stopping.

<Operation> In the method for sealing a protective liquid for a thin film EL panel of the present invention, a wetting liquid as a protective liquid is supplied from an injection hole provided in a rear glass plate,
EL surrounded by the transparent electrode on the glass substrate and the back glass plate
When the inside of the space in which the element is held is injected, the injection hole for the wetting liquid provided in the rear glass plate is sealed with the adhesive. After that, the adhesive is covered with an adhesive having a small moisture permeability coefficient and a glass cap adhered to the rear glass plate by the adhesive. At this time, since the glass cap placed on the back glass plate is temporarily fixed on the back glass plate by a fast-curing adhesive, it has a small moisture permeability coefficient that covers the injection hole while being adhered to the glass cap. The adhesive cures without slipping the glass cap, even in the increased fluid state.

<Examples> Hereinafter, the present invention will be described in detail with reference to Examples shown in the drawings. As shown in FIG. 1, a large number of parallel strip-shaped transparent electrodes 2 are provided on a glass substrate 1, and the transparent electrodes 2 are provided.
An EL element 7 having a smaller area than the electrode region is installed on the upper side. However, here, the EL element 7 is the same as the conventional example in the light emitting layer 14
Is surrounded by the first and second dielectric layers 13 and 15, and a large number of parallel back electrodes 16 are provided on the second dielectric layer 15 in a direction intersecting with the transparent electrode 2. It should be shown in the figure. Then, on the transparent electrode 2 and the glass substrate 1 (which are in contact with both because of the lattice shape), there is a space 4 having a size enough to cover the EL element 7 and a depth of 1 [m / m].
The back glass plate 3 made of soda glass or borosilicate glass formed by sand etching or the like is adhered with a photo-curable resin or an epoxy resin. An injection hole 5 having a diameter of 3 to 10 [m / m] and a depth of about 1 [m / m] is formed on the back glass plate 3, and the outer surface of the injection hole 5 has an appropriate depth. The counter bore 6 is formed, and the tip of the metal pipe 8 for pouring the wetting liquid is inserted and fixed in the pouring hole 5.

Next, the other end of the injection pipe 8 is first connected to an air intake device (not shown), and the air in the space 4 of the rear glass plate 3 is temporarily inhaled by operating the air intake device. The inside of the tank is evacuated by removing it, and then the suction device of the injection pipe is switched and connected to the inside of the silicone oil tank to bring it into a normal pressure state. Because of the pressure, it is sucked into the void 4.

Thus, when the silicone oil is completely injected into the gap 4, the pipe 8 is immediately squeezed in the portion where the injection glass 8 is connected to the rear glass plate 3, that is, in the seat hole 6, as shown in FIG. To form a narrowed portion 8 ', and then the pipe 8 is cut from this portion for temporary sealing. At this time, it is important that the outer end of the residual piece 8 ″ of the pipe is sufficiently lower than the outer surface of the rear glass plate 3 in relation to the next work. That is, the adhesive 9 such as a resin or a photo-curable resin is used for encapsulation and sealing, and the finished state of the adhesive 9 such as a curable resin at this time does not protrude from the surface of the rear glass plate 3.

Next, a flat glass cap 11 of any shape such as a circular shape, a square shape, or a polygonal shape (any other plastic, ceramic, metal, rubber, etc. may be used on the countersink hole 6 of the rear glass plate 3; Glass is used in consideration of the adhesion performance with the glass plate). In this case, the back glass plate 3
On any surface of the glass cap 11, an epoxy resin adhesive 10 and a temporary fixing adhesive 12 selected from any one of an instant adhesive, a thermoplastic resin adhesive, an ultraviolet curable resin adhesive, and the like in advance. Apply at the same time and add. As another bonding procedure, the glass cap 11 may first be temporarily installed with the temporary adhesive 12, and then the epoxy resin adhesive 10 having good permeability may be introduced by a capillary phenomenon.

In addition, since different kinds of temporary fixing adhesive 12 and book attaching adhesive 10 are used as described above, the rear glass plate 3 of the glass cap 11 is prevented in order to prevent both adhesives from being mixed first. By forming the peripheral edge of the surface opposite to the inclined surface 11 ′, it is possible to help prevent the adhesive 12 for temporary fixing from entering the adhesive 10 for bookbinding due to the surface tension of the resin. .

<Advantages of the Invention> The present invention is configured as described above, so that even if the moisture permeability coefficient is large, the resin adhesive having a small moisture permeability coefficient is temporarily fixed by using the resin adhesive having fast curing property. The glass cap is fixed early in the process before the agent hardens. Therefore, the glass cap is securely attached to the predetermined position without being displaced.

In addition, since such a reliable sealing operation is possible, there are few defective parts in manufacturing, the yield is high, and reliable sealing is possible, so that it is possible to maintain stable quality over a long period of time. Have.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention, and FIG. 1, FIG. 2 and FIG. 3 are longitudinal side views of essential parts showing a series of flow of sealing work, and FIG. FIG. 5 and FIG. 6 show a conventional example, FIG. 5 is an enlarged vertical side view of a thin film EL panel, and FIG. 6 is another thin film EL panel of the same as above. FIG. 3 is an enlarged vertical side view of FIG. 1 ... glass substrate, 2 ... transparent electrode 3 ... rear glass plate, 4 ... void 5 ... injection hole, 6 ... counter hole 7 ... EL element, 8 ... injection pipe 8 '... narrow Squeezing part, 8 ″ …… Remaining piece 9 …… Adhesive, 10, 12 …… Adhesive 11 …… Glass cap

Continuation of the front page (72) Inventor Hisashi Kamiide 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (56) Reference JP-A-2-75193 (JP, A) JP-A-60-167296 (JP, A) JP-A 64-2295 (JP, A) Actually opened 63-174195 (JP, U) Actually opened 62-67498 (JP, U) Actually opened 1-95097 (JP, U) Actual Kaihei 2-133894 (JP, U) Actual opening Sho 63-52297 (JP, U)

Claims (1)

[Claims] 1. An EL element is held in a space surrounded by a transparent electrode on a glass substrate and a back glass plate, and a wetting liquid as a protective liquid is injected through an injection hole provided in the back glass plate. In the thin film EL panel consisting of the above, the wetting liquid injection hole is sealed with an adhesive, and then an adhesive with a low moisture permeability coefficient that covers the adhesive and the adhesive is adhered to the rear glass plate. A method of sealing a thin film EL panel with a protective liquid, which comprises temporarily fixing the glass cap on a rear glass plate with a fast-curing adhesive when sealing with a glass cap.