JPS61290694A - 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 Field of Industrial Application The present invention relates to an EL panel among flat display panels that will become increasingly necessary, particularly in the field of office automation, in line with the trend of information society. EL panels differ from liquid crystal and electrochromic display panels in that they are all-solid-state, self-luminous, easy to see even in the dark, and less dependent on viewing angle. In addition, it is thin and lightweight, making it easy to increase the screen resolution, and has the characteristics of no flicker, making it ideal for character and graphic displays for personal computers and word processors.

Conventional technology A general KEL flat panel has a structure in which a transparent electrode, a first insulating layer, a phosphor layer, a second insulating layer, and a back electrode are laminated in this order on a glass substrate. You can also benefit if one is missing.

The transparent electrode and the back electrode are formed into stripes that are perpendicular to each other, and their intersections form light emitting segments. Light emission is observed from the transparent electrode side.The phosphor layer is often based on ZnS, and it contains μ and T as luminescence activators.
Problems to be solved by the bF3-doped invention As described above, since the luminescent layer is made of ZnS, it is susceptible to moisture, and its brightness decreases with driving time in the atmosphere. In particular, when exposed to ultraviolet light, the reaction with moisture is accelerated and the brightness decreases sharply.
This is caused by the peeling phenomenon of the insulating layer. - When peeling occurs, it progresses rapidly, and the number of segments that do not emit light even when a voltage is applied increases. It will be applied. Conventionally, a glass-like cap was placed over the cap, and an insulating material such as silicone oil was filled inside to make it moisture resistant. Since this glass cap adheres to a completely flat EL glass substrate, it was necessary to polish the surface of the part that contacts the substrate.

Additionally, machining glass into a cap shape has the drawback of increasing costs.

The cap can be made of a metal that is easy to manufacture, such as aluminum, but in this case, the coefficient of thermal expansion is significantly different between the cap and the glass substrate, so if the cap is removed in an environment with large temperature changes, the substrate may Damage may occur.

Another method is to directly cover the EL layer up to the back electrode with an inorganic or organic a-retaining film, but these methods
L The operational stability of the panel is poor 1, and the panel is prone to dielectric breakdown. Therefore, a moisture-proofing measure that is easy to manufacture, low cost, and highly reliable is desired.

The present invention is easier to manufacture, lower cost, and
The purpose of the present invention is to provide an EL panel with highly reliable moisture-proof measures.

Means for Solving the Problems In order to achieve the above object, the EL panel of the present invention uses epoxy plastic or epoxy plastic containing a filler as an envelope for covering a glass substrate on which an EL layer is formed.

Function: Epoxy plastics have the best moisture permeability among organic resins, and they also deform more easily than glass or metals due to temperature changes. The glass substrate will not be damaged if it comes off.

Moreover, since it is easy to process and lightweight, it ultimately contributes to the lightweight and low cost of the EL panel.

Example A transparent electrode (indium, tin mixed crystal oxide), S r TiOs first insulating layer, ZnS:M on a glass substrate.
n phosphor layer, Y2O3t' BaTa2O6 laminated type 2nd
Stacking an insulating layer and a back electrode consisting of A/ in this order,
An EL panel as shown in the figure was created. A transparent electrode and
The Il back electrodes are striped and are perpendicular to each other.
A matrix of multiple luminescent segments is formed at the intersection points.

In the figure, 1 is a glass substrate, 2 is a transparent electrode, and 3 is a first
Insulating layer, 4 is phosphor layer, 6 is M2 insulating layer, 6 is AI! The back electrode, 7 is an epoxy plastic cap, and 8 is an epoxy adhesive.

The figure is drawn schematically, and in reality, the EL layer consisting of 2, 3, 4° 6 and 6 is very thin compared to the cap 7 and the glass substrate 1. 7 cap has a thickness of 2 to 311 II oEL! There is an indentation at a depth of 0.6 to 1 nm on the side facing. Mechanical processing of such an epoxy plastic cap is very easy. Even if this cap has undulations or curves along its surface, there is no problem.

This is because of the deformability peculiar to plastics, and the adhesive 8
After attaching to the edge of the cap, place it on the glass substrate 1,
By applying light pressure uniformly from above and below the cap and the glass substrate, the undulations and curves are straightened out, and the adhesive solidifies, so that it adheres to the glass substrate 1. Plastics are preferable for the cap because of their ease of processing, light weight, and corrosion resistance, but epoxy plastics are the best from the standpoint of moisture permeability.

If such a cap is conventionally made of glass, processing it into a similar structure will cost about 10 times more because the edge surface must be flattened so as to come into close contact with the glass substrate.

As the adhesive in step 8, it is preferable to use a jepoxy-based adhesive as it is the material that is least permeable to moisture.

Before attaching the plastic cap, degas the glass substrate on which the EL layer has been formed in a vacuum at 100'C, and then quickly attach the cap to the side on which the EL layer is formed using the above adhesive in a dry atmosphere. Fixed with adhesive.

As a result of a running test of the EL panel constructed as described above, excellent life characteristics were obtained.

In other words, when an EL panel without any seal is operated and emitted in the atmosphere in the same way as when it is used completely, the average brightness will drop to 10~10% after about 100 hours due to the peeling of the thin film.
The value drops to about 30 inches, and non-luminous segments occupy the majority.

On the other hand, in the EL panel of the present invention, no peeling occurred even after 10,000 hours, and the brightness could be maintained at 70% or more.

Therefore, it was judged to have practical life characteristics.

In addition, in a temperature cycle test between -50°C and 100°C, for example, a panel in which the EL layer was covered with an aluminum metal cap of 111II thickness and fixed with adhesive showed that the adhesive part came off after about 50 cycles. No damage was observed in the panel of the present invention even after 100 times.

Although a typical embodiment has been described above, there is no problem even if the epoxy plastic cap contains a filler.

Rather, epoxy plastic filled with glass powder, quartz powder, alumina powder, calcium carbonate powder, etc. is preferable because it lowers the cost of the cap, has a small coefficient of linear expansion, and increases thermal conductivity and mechanical strength.

It is also possible to insert a film-like desiccant between the EL layer and the plastic cap.
It is clear that it may improve the life characteristics of the panel, but not make it worse.

Effects of the Invention The EL panel equipped with the moisture protection device of the present invention has high brightness stability, is easy to manufacture, and is low cost.
It is highly practical and industrially superior due to its lighter weight.

[Brief explanation of drawings]

The figure shows a K equipped with a moisture-proof device according to an embodiment of the present invention.
Ql which is a cross-sectional view of a part of the L panel...Glass substrate, 2...Transparent electrode, 3...First
Insulating layer, 4... Fluorescent layer, 6... Second
Insulating layer, 6... Back metal electrode, 7-...
Epoxy plastic cap, 8...Organic adhesive.

Claims (1)

[Claims] An EL panel characterized in that an epoxy plastic or an epoxy plastic containing a filler is used as an envelope that covers a glass substrate on which an EL layer is formed.