JPH02201889A - El device - Google Patents

Abstract

PURPOSE:To manufacture the above device easily, suppress invesion of humidity and extension of dielectric breakdown, and heighten its durability by forming a sealing covering layer for a multilayered EL film on a transparent substrate while forming a bland layer between them. CONSTITUTION:An insulating layer 3 is formed on a transparent electrode 2, an EL luminescent layer 4 is then formed on the insulating layer, and an insulating layer 5 is so formed as to cover these layers and further an opposite electrode 6 is formed to give a multilayered EL film 7. A heated and fluidized paraffin wax 13 is applied on the film 7, and then a sealing layer 4 of a thermosetting resin solution is formed thereon and a blank layer 13' is formed by heating these layers. An excellently water-repelling stone wax components are contained in the thermosetting resin of the sealing layer 14 so as to heighten humidity resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an EL device that utilizes the electroluminescence (EL) phenomenon, and particularly to a thin film EL device. E
In recent years, L elements are being applied to displays of various devices.

[Prior Art and Problems to be Solved] The attached FIG. 3 shows a conventional thin film EL device, in which a transparent electrode 2, an insulating layer 3, an EL light emitting layer 4,
The second insulating layer 5 and the counter electrode 6 are sequentially laminated to form an EL multilayer film 7, and between the transparent electrode 2 and the counter electrode 6 several tens of
By applying a voltage of Hz to several KHz, active species ions in the EL light emitting layer 4 are excited to emit light.

Conventional thin-film EL devices have had the problem that the EL multilayer film 7 is sensitive to moisture, and its life is significantly shortened when it comes into contact with moisture. For this reason, various measures have been taken to prevent moisture from entering.In the conventional example, the EL multilayer film 7 on the transparent substrate 1 is sealed with a glass cap 8, and silicone oil etc. are placed inside the glass cap 8. (For example, JP-A-61-232595).

However, in order to use the molded glass cap 8 and to hermetically adhere it to the substrate Fi,1, it is necessary to precisely mold the glass cap 8 and to precisely adhere the glass cap 8 to the substrate 1. For this reason, there have been problems in that material costs are high and assembly work is complicated, resulting in a rise in manufacturing costs.

FIG. 4 shows another conventional example in which a moisture-proof protective film 1) is laminated and integrated by covering an EL multilayer film 7 on a substrate 1 and sandwiching a metal foil 12 via an adhesive layer 10.
It protects the multilayer film 7 by blocking moisture from entering (e.g., JP-A-63-170894), and this conventional example has the advantage of being easier and cheaper to manufacture than the previous conventional example. .

By the way, it is difficult to eliminate defects such as minute pinholes when forming an EL multilayer film, and it is known that pinholes in the insulating layer in particular become the starting point for dielectric breakdown and expand the breakdown. It is said that there are several to more than ten pinholes on the order of tens of micrometers per pixel (dot). However, in this prior example, there is a problem in that the heat at the pinhole, that is, the origin of the dielectric breakdown, is blocked by the adhesive layer and other protective films, making it difficult to dissipate the heat, and conversely, the heat is likely to accumulate, causing the dielectric breakdown to expand. .

The present invention solves these problems and provides an EL element that is easy to manufacture and has excellent durability that suppresses moisture intrusion and expansion of dielectric breakdown.

[Means to solve the problem] The present invention relates to an EL element, which includes a transparent electrode on a transparent substrate.

E consisting of an insulating layer, an EL light emitting layer, a second insulating layer, and a counter electrode
An L multilayer film is formed, and a sealing coating layer of the EL multilayer film is formed via a space layer, and preferably a volatile component and/or a thermoplastic resin is used as the material for forming the space layer. Consisting of

In the present invention, a sealing layer may be formed on the EL multilayer film by using a thermosetting resin, room temperature curing resin, etc. molded by a molding method or the like via a space layer, and the sealing layer is formed using an adhesive. It can be attached to the substrate by suitable means such as thermocompression bonding or thermocompression bonding.

By providing the space, heat at the origin of dielectric breakdown in the EL multilayer film can be easily dissipated, and the expansion of the breakdown can be suppressed.

However, in order to improve heat dissipation, it is preferable that the spacing between the space layers be 100 μm or more.

The sealing layer can be made of various resins such as phenol, melamine, alkyd, etc., but in order to further suppress the permeation of moisture, it is recommended that zeolite with a pore size of 5 Å or less be mixed in at about several 1 Ilt% to about ten IIIt%. is preferred. Other means for forming the spatial layer include materials forming the spatial layer;
In other words, ingredients such as naphthalene and camphor that volatilize and sublimate, or thermoplastic resins such as polyethylene that have a low melting point and are easily fluidized, are applied to the space forming part, and the former is volatilized by heating, and the latter is liquefied by heating and becomes porous. It can be absorbed into the thermosetting resin sealing layer.

Note that the porous thermosetting resin can be easily formed by mixing a low boiling point solvent or by other appropriate known means, and there is no need to make it highly porous.

The present invention will be explained in detail with reference to Examples below.

[Example 1] As shown in the attached Figure 1, a transparent T! The X-pole 2 is formed by sputtering and patterned by etching. Next, this transparent T4 pole 2
An insulating layer 3 made of Ta205 is formed thereon by reactive sputtering. Furthermore, zinc sulfide (ZnS:Mn) doped with manganese is deposited on this insulating layer 3.

A light-emitting layer 4 made of Mn=Q, 3atχ) is formed by sputtering. Cover these with Ta
A second insulating layer 5 made of 206 is formed by a reactive sputtering method, and an aluminum film for a voltage application electrode is further formed on the second insulating layer 5 by a sputtering method. The aluminum film is etched and patterned to form a counter electrode 6 to form an EL multilayer film 7.

In this embodiment, a thermoplastic resin containing a mineral wax component such as paraffin wax is used as the material 13 forming the space layer.

That is, the paraffin wax 13 heated and fluidized is applied onto the EL multilayer film 7, and the sealing layer 14 made of a thermosetting resin solution as described above is further applied thereon. By then heating these, the low boiling point solvent in which the thermosetting resin is dissolved is scattered, while the fluidized paraffin wax enters and is absorbed into the core by capillary action or the like. Thus, a space Jli1.3 is formed, and the sealing layer 14 has extremely high moisture resistance by containing a hydrophobic wax component in the thermosetting resin.

In addition, to form the thermosetting resin sealing layer 14, a mold corresponding to the outer surface 14 of the resin 14 is placed on the base film in advance, and the thermosetting resin 14 is melted between the space layer forming material 13 and the mold. It is also possible to inject a liquid and allow it to harden.

FIG. 2 shows another embodiment of the present invention. In a large-area thin film EL device, the spacing can be maintained by interspersing granular spacers 15 such as glass beads in the space layer 13. Further, the sealing layer 14 is covered with poly 3
Moisture resistance is further improved by forming a moisture-proof film 16 such as fluoroethylene or polytetrafluoroethylene.

Test examples attached A conventional thin film EL device with the configuration shown in FIG. 3 (Comparative Example 1), a conventional thin film EL device with the configuration shown in FIG. 4 (Comparative Example 2)
), and when the devices according to the present invention shown in Fig. 1 were prototyped and operated for 10,000 hours, the dielectric breakdown of Comparative Example 2 was enlarged, and it was observed that the size exceeded 100 μmφ in many places. .

- No expansion of dielectric breakdown was observed in the strength-grip invention and in Comparative Example 1, but in Comparative Example 1, manufacturing of the glass cap and installation of the board required an extremely long time and effort, which caused problems in terms of cost. The present invention having 0 is the most excellent in that it can be manufactured easily and at low cost, and can also suppress the expansion of dielectric breakdown.

[Effects of the Invention] According to the present invention, the structure is simple and easy to manufacture;
It also suppresses the intrusion of moisture and the spread of dielectric breakdown, and has the effect of being resistant to deterioration even during long-term operation.

[Brief explanation of the drawing]

1 to 4 are partial side cross-sectional views of the thin film EL element, and FIG. Fig. 2 is the one according to the present invention, Fig. 3. FIG. 4 is related to the prior art.

Claims (2)

[Claims] (1) An EL multilayer film consisting of a transparent electrode, an insulating layer, an EL light emitting layer, a second insulating layer, and a counter electrode was formed on a transparent substrate, and a sealing layer of the EL multilayer film was further formed via a space layer. An EL element characterized by the following. (2) The EL device according to claim (1), wherein a volatile component and/or a thermoplastic resin are used as materials for forming the spatial layer.