JPS6068587A - Sealing structure of thin film 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] Technical Field> The present invention utilizes EL (EL) technology by applying an alternating electric field.
r.

Luminescence) Thin that exhibits luminescence B) E
This invention relates to a structure for injection and sealing of a fluid for protecting N-film EL elements, which is an effective technology for EL display panels using L elements.

<Prior Art> Conventionally, with regard to AC-operated thin film EL elements, a high electric field (about 106 V/cm) is regularly applied to the light emitting layer to improve dielectric strength, luminous efficiency, stability of operation, etc.
1-2. Ow t% Mn (or Cu.

A three-layer structure Zns:Mn (or Zn5e, M
n) EL devices have been developed and improvements in light emitting characteristics have been confirmed. This thin film EL element emits light with high brightness when an alternating current electric field of several KHz is applied, and has a long lifespan.

The basic structure of a ZnS:Mn thin film EL device is shown in FIG. 1 as an example of a thin film EL device.

The structure of a thin film EL element will be explained in detail based on FIG.
l2O3, Si3N4. A first dielectric layer 3 made of SiO2 or the like is formed in an overlapping manner by sputtering, electron beam evaporation, or the like. The first dielectric layer 3 contains ZnS:M
A ZnS light emitting layer 4 obtained by electron beam evaporation of n-sintered pellets is formed. At this time, Z for vapor deposition
As the nS:Mn sintered pellet, a pellet in which Mn, which is an active substance, is set at a concentration depending on the purpose is used. Zn
A second dielectric layer 5 made of the same material as the first dielectric N3 is laminated on the S light-emitting layer 4, and furthermore, a back electrode 6 made of a metal oxide layer is formed by vapor deposition thereon.

The transparent electrode 2 and the back electrode 6 are connected to an AC power source 7. is connected to, and the thin J-type E L element is driven.

When an AC voltage is applied between the electrodes 2 and 6, the ZnS light emitting layer 4
The alternating current voltage is induced between the dielectric layers 3 and 5 on both sides of the ZnS light emitting layer 9. Therefore, the electric field generated in the ZnS light emitting layer 4 excites and accelerates the electrons into the conduction band and obtains sufficient energy. directly excites the Mn luminescent center, and when the excited Mn luminescent center returns to the ground state, it emits yellow light. That is, electrons accelerated by a high electric field excite the electrons of Mn atoms that have entered the Zn site, which is the luminescence center, in the ZnS luminescent layer 4, and when they fall to the ground state, they emit bright light.

The thin film EL element having the structure described above can be used as a flat thin display device that takes advantage of the space factor to display characters, symbols, static images, etc. It can be used as a display means for images, moving images, etc., and is very effective.

However, the dielectric layer of a thin film EL element contains many pinholes and microcracks that occur during the manufacturing process, and moisture, etc. enters the ZnS light emitting layer 4 through these defects, resulting in heat generation due to EL emission loss and delamination. , resulting in deterioration of device characteristics, etc. In order to solve all of the above problems, as shown in Fig. A sealing method has been proposed as an improved technology that prevents and fixes the expansion of minute thermal damage areas, protects against moisture in atmospheric environments, has heat dissipation effects, and is also effective against vibration and deflection.

This thin film EL panel adopts a matrix electrode structure in which the transparent electrode 2 and the back electrode 6 shown in FIG. The position where 6 intersects in plan view corresponds to one picture element of the panel.

To explain based on FIG. 2, transparent electrodes 2 and a first dielectric layer 3 are arranged in parallel on a glass substrate 1 at a constant interval.
, a ZnS light emitting layer 4 is sequentially laminated, and an Al20 film is superimposed on a 5iaN4 film and a Si3N4 film on the ZnS light emitting layer 4.
A second dielectric layer 5 made of 3M is laminated in a two-layer structure, and back electrodes 6 are arranged in parallel at a constant pitch in a direction perpendicular to the transparent electrode 2.
A thin film EL element is formed on the top of the thin film EL element. In order to prevent this thin film EL element f: a back glass plate 11 is placed facing the glass substrate l via a spacer lO, and each joint of the glass substrate 1, spacer 10 and back glass plate 11 is fixed with adhesive]2. It is sealed and forms an envelope for the thin film EL device. A thin film EL element is housed in the envelope, and an injection fluid 13 for protecting the thin film EL element, such as silicon oinope vacuum grease, is filled and sealed.

The conditions required for the injection fluid 13 are (1) permeability into pinholes, (2) high dielectric strength, (3) excellent heat resistance and moisture resistance, and (4) high resistance to thin-film EL element constituent films. (5) It is desirable that the material is a fluid material with a low vapor pressure and coefficient of thermal expansion, but it is particularly important that it has permeability into pinholes, has a somewhat high dielectric strength voltage, and does not react with the films constituting the thin-film EL element. It takes. The spacer IOK is provided with one to several micro injection holes 14 for injecting silicone oil or the like. Further, one end of the lead terminal portion 15 of the transparent electrode 2 and the back electrode 6 extends onto the glass substrate l outside the envelope via the joint between the glass substrate 1 and the back glass plate 11.
<Object of the Invention> The present invention provides a fluid sealing structure in a thin film EL panel filled with the fluid for protecting the thin film E'L elements. The purpose is to provide improved technology regarding.

<Embodiment> FIG. 3 is a cross-sectional view of a thin film EL panel for explaining one embodiment of the present invention.

Transparent electrodes 2 are arranged parallel to each other in a strip shape at a constant pitch on a glass substrate 1''2, thereby forming a thin film EL element 16. A dish-shaped rear glass plate 17 is superimposed on the glass substrate 1 to accommodate the thin film EL element 16, and the thin film EL element is housed in the internal gap. The joint between the glass substrate 1 and the rear glass plate 17 is sealed with an adhesive such as a photocurable resin or an epoxy resin. Details of the manufacturing process of the back glass plate 17 are shown in FIG. 4.As the back glass plate 17, soda glass, borosilicate glass, etc. are used.
The housing portion of the EL element structure is formed into a recess by sand etching or the like to a depth of about 100 mm. An injection hole 18 for fluid injection is formed at one corner of the concave molding area, and a hollow injection pipe 1975 is inserted thereinto. The injection pipe 19 is made of metal and is fixed to the injection hole 18 with adhesive. Rear glass plate 1 corresponding to the outer end of injection hole] 8
At position 7, there is a hole with a diameter of 5 to 10 - larger than the diameter of the injection hole 18.
A hole 21 of approximately 100 mm is formed. The depth of the hole 21 is approximately 2-1. The tip of the injection pipe 19 is inserted into a tank containing an insulating protective fluid such as silicone oil, and the fluid is injected into the entire panel. When the injection operation of the injection fluid is completed, as shown in FIG. 5(A), the injection pipe 19 near the envelope joint is crimped to complete the temporary sealing. After that, the temporary sealing part is injected/< Eve 19 is cut as shown in FIG. The agent 20 is inserted into the hole 21 (depth D) of the rear glass plate 17 as shown in FIG. 5(C).
It is attached so that it can be stored inside. Next, the flat glass key 8/knob 22f is covered with an adhesive on the back glass plate 17 of the sealing part of the injection pipe 19, creating a double sealing structure as shown in FIG. 5(C). The structure in which a concave portion is provided in the glass cap is obtained by temporarily sealing the injection pipe 19 by pressure on the rear glass plate 17 as shown in FIG. 6(A), and cutting the injection pipe 19 as shown in FIG. 6(B). After that, a glass gear 5. is coated with resin and has a concave portion as shown in FIG. 6(C). P2
3 is bonded to the back glass plate 17, but compared to this embodiment, by providing a concave portion in the rear glass plate 17 and storing the sealing portion in the concave portion, the fifth
If the plate thickness of the flat glass cap 22 in Figure (C) is 'tT+, and the plate thickness of the glass cap 23 provided with the concave portion in Figure 6 (C) is T2, the overall plate thickness is thinned by T2-T+. By doing so, it becomes Noh. As the adhesive for bonding the flat glass cap 22 to the back glass plate 17, a photocurable adhesive or the like is used. In addition, the flat glass cap 22 is made of the same material as the rear glass plate ] 7 and has a size of 15 WrmX 1
5 Thickness of about +rrm 0.1 to 1. One with O1mR is used.

The rear glass plate 17 may be made of a glass material formed into a dish shape instead of a flat glass plate formed into a concave shape by sand etching. After the fluid injection hole 18 is bored, the outer end thereof is expanded into a large diameter hole 21 by counterboring, and then the injection pipe 19 is inserted into the fluid injection hole 18 and fixed with adhesive.

The injection pipe 19 is preferably one whose interior can be easily sealed by pressure bonding, and generally a metal member such as aluminum, copper, or iron is used. To inject the insulating protection fluid, insert the tip of the injection pipe into the tank containing the fluid inside the vacuum container.
A method is then applied in which the fluid is injected into the envelope via the injection pipe 19 by returning to atmospheric pressure.

The insulating protective fluid is filled especially with the intention of moisture-proofing the thin film EL element 1G, and therefore the injection pipe 19 and the fluid injection hole 8 must be reliably sealed after the fluid is injected. In the above embodiment, this sealing structure is made into a double structure to ensure reliability. Furthermore, since the insulating protective fluid such as silicone oil has a high coefficient of thermal expansion, it may leak from the multi-fluid injection hole 18 due to volumetric expansion when used at high temperatures. However, in the sealing structure of this embodiment, this leaked fluid is covered with the flat glass cap 22, so it is stored in the counterbore hole 21 and does not leak outside. Effects> As described above, the thin film EL panel sealing structure of the present invention has a concave part in the rear glass plate that allows the sealing part to be inserted in place of the conventional glass cap with a concave part, and also has a flat glass cap. Because it is covered and double-sealed, it is possible to make the display thinner while still guaranteeing conventional reliability.
The practical measurement becomes more important.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a specific structure of a thin film EL element. FIG. 2 is a diagram illustrating a main part of an example of a conventional thin film EL panel. FIG. 3 is a diagram showing the main part of a thin film EL panel for explaining one embodiment of the present invention. FIG. 4 is a cross-sectional view of the back glass plate used in the thin film EL panel of FIG. 3. FIGS. 5(A), 5(B), and 5(C) are manufacturing process diagrams illustrating one embodiment of the present invention. Figure 6 (A) (B) (C
) is a manufacturing process diagram illustrating an embodiment in which a conventional glass cap is provided with a concave portion. glass substrate, 16 thin film EL element, 17 - back glass plate, 18 - injection hole, 19 - injection pipe, 2
0 - Adhesive, 21 - Concave part, 22 - Flat glass cap agent Patent attorney Yoshihiko Fukushi (and 2 others) Broom 1 Figure 2 Figure 3 (A) (B) (C) Knee; □ 5 Figure

Claims (1)

[Claims] 1. In a thin film EL panel containing a protective fluid, a thin film EL element and insulation for the thin film EL element are placed in an envelope consisting of a translucent front substrate and a back plate. An injection hole for injecting an insulating protection fluid is bored, and a counterbore hole with a large diameter is formed at the outer end of the injection hole, and the opening of the injection hole is sealed within the counterbore hole. It was sealed with a glass cap!
Sealing structure of thin film EL panel with one characteristic.