JP2000068051A - El display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress shortening of luminous life of electroluminescence(EL) and lowering of luminance by surely preventing infiltration of moisture from respective electrode terminal parts of a back electrode and a front electrode. SOLUTION: In this EL display device 12, a back electrode 2, an insulating layer 3, a luminous layer 4 and a front electrode 5 are sequentially laminated on a substrate 13, and they are sealed with a sealant 14, then AC voltage is impressed between both the electrodes 2, 5 to cause the luminous layer 4 to emit light. Here, a pair of through-hole electrodes 18a, 18b are provided to the substrate 13. External lead-out electrodes 16a, 16b are provided to the though-hole electrodes 18a, 18b on the back electrode 2 side of the substrate 13, to block the through-holes. Thus, the back electrode 2 and the front electrode 5 are electrically connected respectively to the external lead-out electrodes 16a, 16b. Furthermore, external electrodes 17a, 17b are provided on the side opposite to the back electrode 2 side of the substrate 13 to connect to the respective through-hole electrodes 18a, 18b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a display device using electroluminescence (EL), and more particularly to an EL display device for preventing intrusion of moisture from around external electrodes.

[0002]

2. Description of the Related Art Conventionally, there is a display device using an EL light emitting element as a backlight of a liquid crystal display device or a light source of various displays. Conventionally, as this type of EL display device, for example, one having a structure as shown in FIGS. 3 and 4 is known. This EL display device 1 is in the form of a sheet, and has a laminated body 6 composed of a back electrode 2, an insulating layer 3, a light-emitting layer 4 and a front electrode 5, and an upper and lower covering the outer surfaces of the back electrode 2 and the front electrode 5. The hygroscopic materials 7a, 7b, and the hygroscopic materials 7a, 7b,
7b and a package film 10 with the outside sealed. The back electrode 2 and the front electrode 5 are provided with current collecting bands 8a and 8b, respectively.
Lead out the electrode lead terminals 9a, 9b. The light emitting layer 4 emits light when an AC voltage of about 35 to 150 V is applied between the back electrode 2 and the front electrode 5 from the electrode lead terminals 9a and 9b.

[0003]

However, in the above-mentioned conventional EL display device 1, the upper and lower surfaces of the laminated body 6 composed of the back electrode 2, the insulating layer 3, the light emitting layer 4 and the front electrode 5 are made of a hygroscopic material 7a. , 7b and package film 1
0, the external moisture is gradually absorbed from the gap 15 between the electrode lead terminals 9a and 9b drawn out from the back electrode 2 and the front electrode 5, and if it is used for a long period of time, light emission will not occur. There is a problem in that moisture penetrates into zinc sulfide as a luminescent agent of the layer 4 and discolors the luminescent layer 4 to black, which causes a reduction in life and a reduction in emission luminance.

Accordingly, the present invention provides an EL display device in which the invasion of moisture from the electrode terminal portions of the back surface electrode and the front surface electrode is surely prevented, thereby suppressing a reduction in the EL light emission lifetime and light emission luminance. To provide.

[0005]

In order to solve the above problems, an EL display device according to a first aspect of the present invention seals a back electrode, an insulating layer, a light emitting layer, and a surface electrode which are sequentially laminated on a substrate. In an EL display device which is coated with a material and emits a light emitting layer by applying an AC voltage between the back electrode and the front electrode, a pair of through-hole electrodes are provided on the substrate,
An external extraction electrode is provided on the back electrode side of the substrate of the through hole electrode to close the through hole, and the back electrode and the surface electrode are electrically connected to the external extraction electrode, respectively, and are opposite to the rear electrode side of the substrate. Each side electrode is provided with an external electrode for conducting with each through-hole electrode.

According to a second aspect of the present invention, in the EL display device, the external extraction electrode is formed by printing from a conductive paint having a higher viscosity than that of the through-hole electrode. It is characterized by.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an EL display device according to the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a cross-sectional structure of an EL display device 12 according to the present invention. In the EL display device 12, a back electrode 2, an insulating layer 3, a light emitting layer 4, and a front electrode (ITO electrode) 5 are sequentially laminated on the surface of a substrate 13 made of glass or the like, and the whole is made of a transparent glass or resin. The structure is covered with the stopper 14. Also, through holes are formed in the substrate 13 at two appropriate locations and penetrate the upper and lower surfaces, and through hole electrodes 18a and 18b are formed in each of the through holes to conduct with the back surface electrode 2 and the front surface electrode 5, respectively.

On the other hand, on the upper surface of the substrate 13, an external electrode 16a for the back electrode 2 and an external electrode 16b for the front electrode 5 are provided with the through-hole electrodes 18a, 18a, respectively.
It is formed so as to close b. External electrodes 17a and 17b are provided on the lower surface of the substrate 13 at the periphery of the through-hole electrodes 18a and 18b, respectively.
The external extraction electrode 16a on one side is electrically connected to the external electrode 17a via the through-hole electrode 18a, and the external extraction electrode 16b on the other side is electrically connected to the external electrode 17b via the through-hole electrode 18b. .

The through-hole electrodes 18a, 18b and the external extraction electrodes 16a, 16b are formed of a conductive paint such as silver-palladium. First, a silver-palladium paint having a certain viscosity is applied to the substrate 1 from the back electrode 2 side.
3, the silver-palladium paint is drawn down by sucking it from the opposite side of the substrate 13, and adheres to the inner peripheral surface of the through-hole to form the through-hole electrode 18a,
18b are formed. Next, a silver-palladium paint having a slightly higher viscosity is placed on the through-hole in the same manner as described above, and is sucked from the opposite side of the substrate with a weaker suction force than before, and the silver-palladium paint is deformed into a flat shape. To close the top surface of the through-hole,
External extraction electrodes 16a and 16b connected to the electrodes 18a and 18b are formed. As described above, the silver-palladium paint is printed twice in succession, and then fired at a high temperature of about 750 ° C. to form both electrodes. Finally, silver-palladium paint is printed on the periphery of the through hole from the opposite side of the substrate 13, and the external electrode 17 connected to the through hole electrodes 18a and 18b is printed.
a and 17b are formed and fired again at a high temperature of about 750 ° C. As described above, since the substrate 13 is exposed to high temperatures many times, it is desirable to use a high heat-resistant glass. The external electrodes 17a, 17b are connected to the external extraction electrodes 16a,
As in the case of 16b, it is needless to say that the through hole can be closed. It is also possible to use a conductive paint other than silver-palladium.

A back electrode 2 is formed on the upper surface of the substrate 13.
3 or by depositing a conductive paint on the substrate 1
3 can be formed by screen printing or the like. The back surface electrode 2 is connected to the above-described external extraction electrode 16a.
, And an insulating space 22 is provided therearound so as not to contact the external extraction electrode 16b on the surface electrode 5 side. The insulating space 22 can be easily formed by covering the outer extraction electrode 16b and its periphery with a mask when the back electrode 2 is formed.

An insulating layer 3 is formed on the back electrode 2 by printing. The insulating layer 3 is for protecting the light emitting layer 4 from electrical breakdown, and is made of barium titanate having a high withstand voltage. Since the paint in which barium titanate is dispersed has a high light reflectance, it also serves as a reflector for reflecting the light emitted from the light emitting layer 4 to the surface electrode 5 side. When printing the insulating layer 3, a circular space 23 is formed around the insulating space 22 so as to escape the external extraction electrode 16 b corresponding to the insulating space 22. The size of the circular space 23 depends on the size of the insulating space 22. Formed slightly smaller. By forming the circular space 23 slightly smaller than the insulating space 22 in this manner, a step portion 24 is formed between the edge of the insulating space 22 of the back electrode 2 and the edge of the circular space 23 of the insulating layer 3. Will be.

Light emitting layer 4 laminated on insulating layer 3
Is formed by dispersing a phosphor powder in an organic binder. Zinc sulfide (ZnS) is used as a base material of the phosphor powder, and C is used as an activator or coactivator as a luminescent center.
Various emission colors can be obtained by adding u, Cl, I and Mn atoms. The phosphor matrix to which such an activator has been added is made into a paint, which is screen-printed to form a light-emitting layer 4 having a thickness of about 50 to 100 μm on the insulating layer 3. At the time of this printing, a circular space 25 having the same size as the circular space 23 of the insulating layer 3 is provided so as not to come into contact with the external extraction electrode 16b.

After the back electrode 2, the insulating layer 3, and the light emitting layer 4 are laminated as described above, the surface electrode 5 is printed on the light emitting layer 4, and at this time, the surface electrode 5 is formed in a circular shape of the light emitting layer 4. The space 25, the circular space 23 of the insulating layer 3 and the insulating space 22 of the back electrode 2 are also penetrated and printed on the upper surface of the external extraction electrode 16b. Circular space 2 of light emitting layer 4
5 and the circular space 23 of the insulating layer 3 are smaller than the insulating space 22 of the back electrode 2, and a step 24 is formed between the circular space 23 and the insulating space 22. 16b does not come into contact with the back surface electrode 2,
The insulation between the back electrode 2 and the front electrode 5 is maintained. The conductive portion 20 may be in contact with the insulating layer 3 and the light emitting layer 4 without any problem.

The paint for forming the surface electrode 5 is as follows:
Indium oxide is doped with tin oxide and ITO (Indi
um Tin Oxide) Powder is mixed with transparent resin to make paint.

The back electrode 2, the insulating layer 3, the light emitting layer 4 and the surface electrode 5, which are sequentially laminated on the substrate 13, are
The sealing material 14 is sealed by bonding the sealing material 14 to a sealant 19 applied around the substrate 13. The sealing material 14 protects the light-emitting layer 4 from external moisture and transmits light emitted from the light-emitting layer 4, and is made of a material such as glass, metal, or epoxy resin having light transmittance. You. In addition, as the sealing agent 19, silicone resin, acrylic resin, epoxy resin, or the like is used.
The composition is cured by any of ordinary temperature curing, heat curing, or UV (ultraviolet) curing.

The EL display device 12 having the above configuration
Means that one of the through-hole electrodes 18a is connected to the external extraction electrode 1
6a, and the other through-hole electrode 18b is connected to the external extraction electrode 16b and the conducting portion 20a.
Through the surface electrode 5 through the
By mounting the EL display device 12 on the surface, a predetermined AC voltage can be applied between the back electrode 2 and the front electrode 5 from the external electrodes 17a and 17b.

The through-hole electrodes 18a, 18b opened in the EL substrate 13 are connected to the external extraction electrodes 16a, 16b.
Therefore, it is possible to reliably prevent external moisture from entering the inside through the through-hole electrodes 18a and 18b. Further, in this embodiment, since the inside is sealed by the substrate 13 and the sealing material 14, moisture does not enter the inside from other parts.

[0018]

As described above, the EL according to the present invention is provided.
According to the display device, since the through-hole electrode provided on the substrate is closed by the external extraction electrode, and the entire EL is completely sealed with the sealing material, external moisture or moisture may enter the inside of the EL. In addition, it is possible to prevent the life of the EL and the reduction of the emission luminance.

Further, according to the EL display device of the present invention, since the electrode for taking out the outside is made of a conductive paint having a higher viscosity than that of the through-hole electrode, it is formed by printing over the through-hole electrode. Blockage of the through-hole electrode is ensured, and invasion of moisture from the through-hole electrode can be completely prevented.

Further, by forming the back electrode and the external electrode led out from the front electrode on the back side of the substrate, the EL display device can be directly surface-mounted on the motherboard,
Connection with circuit components such as SMD (Surface-Mounted Device) LEDs, chip resistors, and chip capacitors becomes easy.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an EL display device according to the present invention.

FIG. 2 is a bottom view of the EL display device according to the present invention.

FIG. 3 is a perspective view showing a configuration of a conventional sheet-shaped EL display device.

FIG. 4 is a sectional view of a conventional sheet EL display device.

[Explanation of symbols]

 Reference Signs List 2 back electrode 3 insulating layer 4 light emitting layer 5 surface electrode 12 EL display device 13 substrate 14 sealing material 16a, 16b external extraction electrode 17a, 17b external electrode 18a, 18b through-hole electrode

Claims (2)

[Claims] 1. A back electrode, an insulating layer, a light emitting layer, and a surface electrode sequentially laminated on a substrate are covered with a sealing material, and an AC voltage is applied between the back electrode and the surface electrode to form a light emitting layer. In the EL display device that emits light, a pair of through-hole electrodes is provided on the substrate, an external extraction electrode is provided on the back electrode side of the substrate of the through-hole electrode to close the through-hole, and the back surface electrode and the surface electrode are connected to the external electrode. An EL display device comprising: an external electrode that conducts to an extraction electrode; and an external electrode that conducts to each through-hole electrode on a side of the substrate opposite to the back electrode. 2. The EL display device according to claim 1, wherein the external take-out electrode is formed by printing a conductive paint having a higher viscosity than that of the through-hole electrode on the through-hole electrode. .