JPH0119757B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to the structure of an EL (Electro-Luminescence) element.

Prior Art EL elements can be selected from a variety of shapes and sizes and are used as surface light sources for illumination or for instruction/display panels. For example, a thin film EL device generally has a plate shape, with a transparent electrode on a glass substrate, a first insulating layer made of a metal oxide such as Ta ₂ O ₅ , and a phosphor such as ZnS with Mn.
A light-emitting layer made of an activator such as, a deposit made of yttrium oxide (Y ₂ O ₃ ), magnesium oxide (MgO), etc., a second insulating layer made of tantalum oxide (Ta ₂ O ₅ ), etc., and a back surface. A double insulation structure in which each layer of the electrode is sequentially laminated by vapor deposition or sputtering, or a single insulation structure in which only the second insulation layer is used without using the first insulation layer is adopted. Among these, the adhesion layer is interposed between the light emitting layer and the second insulating layer to prevent peeling between the two layers, but this adhesion layer itself is EL
This causes an increase in man-hours when assembling the device, and the adhesion layer cannot sufficiently prevent peeling.
As a result, the light-emitting layer is exposed to the outside air, and moisture and the like can enter the EL element from the outside, making it impossible to obtain sufficient light-emitting characteristics.

Purpose In view of the above circumstances, the present invention provides an EL element that can completely prevent separation between a light emitting layer and an insulating layer, and does not require a special adhesion layer or the like for this purpose.

Summary According to the present invention, the above object is achieved by forming a metal oxide layer on the surface of the light emitting layer which has been subjected to oxygen ion bombardment treatment.

EXAMPLES Hereinafter, the present invention will be explained in detail based on illustrated examples. In FIG. 1, 1 is a glass substrate;
2 is a transparent electrode formed by vapor deposition or sputtering on a glass substrate 1 such as indium oxide (ITO), and 3 is a first electrode formed by vapor deposition or sputtering on a metal oxide such as Ta ₂ O ₅ . In the insulating layer 4, a phosphor such as ZnS is attached to the first insulating layer 3 by vapor deposition or sputtering, and then the surface is subjected to oxygen ion bombardment treatment by a method such as electric discharge in an oxygen atmosphere to form a thin oxide layer. 5 is a second insulating layer in which a metal oxide such as Ta ₂ O ₅ is formed by vapor deposition or sputtering on the light emitting layer 4 and shields the light emitting layer 4 from the outside air; 6 is a second insulating layer; A back electrode attached to layer 5.

The EL element of the present invention is constructed as described above, and the surface of the light-emitting layer 4 is subjected to O ₂ ion bombardment treatment, and since an extremely thin area of the surface is oxidized, Ta The adhesion of the second insulating layer 5, which is a metal oxide such as ₂ O ₅ , is significantly improved, and no peeling occurs between it and the light emitting layer 4. Therefore,
The insulation effect for the light emitting layer 4 is sufficiently ensured,
When driving an EL element, abnormal discharges are reduced, operation becomes stable, and electrical energy loss is reduced. Furthermore, since the adhesive force between the light emitting layer 4 and the insulating layer 5 is strong, the mechanical strength is improved, and since the light emitting layer 4 is completely shielded from the outside air, it is not exposed to the atmosphere and can be chemically removed. It is also stable. Furthermore,
Since there is no need to provide a special adhesion layer as in the past, there is no impedance due to the adhesion layer, making it possible to drive at low voltage and reduce power consumption.
The process for manufacturing EL elements can also be simplified.

FIG. 2 shows another embodiment. According to this embodiment, a light emitting layer 4 is formed on a transparent electrode 2 without using a first insulating layer 3, and the surface thereof is subjected to O ₂ ion bombardment treatment and then a second insulating layer 4 is formed on the transparent electrode 2. It has a single insulation structure in which an insulation layer 5 is formed. In this case, with single insulation of only the first insulating layer 3, the light emitting layer 4 will come into contact with the outside air.
A second insulating layer is used.

In such a single insulation structure, the light emitting layer 4 is covered with the second insulation layer 5 and is completely shielded from the outside air, and the adhesion between them is strengthened, so that the first insulation layer 3 and the second insulation layer 5 As in the case of a double insulating structure consisting of both, the effect of preventing peeling between the light emitting layer 4 and the second insulating layer 5 and the improvement of electrical, mechanical, and chemical stability can be achieved. Further, since the first insulating layer 3 is not used and the structure is simplified, the manufacturing process is further simplified.

In the above embodiment, the EL light of the light emitting layer 4 is extracted from the glass substrate 1 side, but it is also possible to extract the EL light from the back electrode 6 side while maintaining the basic structure. In this case, for example, an opaque substrate such as ceramic is used as the glass substrate 1,
Change the transparent electrode 2 to an opaque electrode, and change the back electrode 6 to I.
A transparent electrode made of TO or the like is used. Furthermore, if both electrodes 1 and 6 are transparent electrodes, the EL light of the light emitting layer 4 can be extracted from both sides of the surface of the EL element.

Note that the light emitting layer 4 subjected to _O2 ion bombardment according to the present invention can be applied to a conventional structure having an adhesion layer made of Y ₂ O ₃ etc. It is possible to improve the peeling prevention effect with No. 5.

Effects of the Invention As described above, according to the EL element according to the present invention,
Peeling between the light emitting layer and the insulating layer can be completely prevented, and the light emitting layer is protected and the light emitting characteristics are improved.
Since the structure can be simplified and manufacturing costs can be reduced, the practical effect is extremely large.

[Brief explanation of drawings]

FIG. 1 has a double insulation structure according to the present invention.
FIG. 2 is a partial cross-sectional view of an EL element having a single insulation structure according to the present invention. DESCRIPTION OF SYMBOLS 1... Glass substrate, 2... Transparent electrode, 3... First insulating layer, 4... Light emitting layer, 5... Second insulating layer, 6... Back electrode.

Claims (1)

[Scope of Claims] 1 A light emitting layer and at least one insulating layer covering the light emitting layer are provided between a pair of electrode plates, the surface of the light emitting layer is subjected to oxygen ion bombardment treatment, and the insulating layer is coated with a metal oxide. An EL element characterized by the following: 2. The EL device according to claim ₁ , wherein the metal oxide is _Ta2O5 .