JPS62177896A - El panel structure - 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] [Summary] The present invention is aimed at stabilizing the electronic level near the interface of the light-emitting layer of an EL panel to stabilize the light-emitting characteristics. This goal is achieved by providing an intermediate layer that can create a stable interfacial electronic state between the two.

[Industrial application field]

The present invention relates to an EL panel, and more particularly to a structure of an EL panel that can stabilize the light emitting characteristics of the panel.

EL panels have a light-emitting layer formed between a transparent electrode and a back electrode, and are widely used for various displays and light sources.

In such an EL panel, stabilizing the light emission characteristics is an important issue.

[Conventional technology]

The structure of this type of conventional EL panel is shown in FIG. In the figure, 1 is a glass substrate, 2 is a transparent electrode, 3 is a light emitting layer of a ZnS polycrystalline film containing a luminescent center impurity, and 4 is a back electrode. The light emitting layer 3 is formed on the transparent electrode 2 formed on the substrate 1 with a first insulating layer 5 interposed therebetween, and a second insulating layer 6 is formed between the light emitting layer 3 and the back electrode 4. . The light emitting layer 3 is formed by vacuum deposition or sputtering.

[Problem that the invention seeks to solve]

However, in the conventional panel structure as described above, Zn
A stable interfacial electronic state could not be created between the S light emitting layer and the second insulating layer, and the light emitting characteristics could not be stabilized.

[Failure to solve the problem]

The present invention provides a structure of an EL panel that can solve the above-mentioned problems, and as a means for this purpose, the structure shown in FIG. 1 is adopted.

That is, in the present invention, between the light emitting layer and the second insulating layer,
A Zn Se intermediate layer that does not contain luminescent center impurities and an oxide insulator intermediate layer are formed in this order from the luminescent layer side.

[Effect]

The Zn Se intermediate layer, which does not contain luminescent center impurities, plays a role in eliminating unnecessary electronic levels caused by impurities or disordered crystallinity between the luminescent layer and the oxide insulator intermediate layer. Furthermore, since the amount of impurities in ZnSe is easier to control than in the case of ZnS, etc., it is possible to artificially control the electronic level between the light emitting layer and the second insulating layer.

The oxide insulator intermediate layer is formed by sputtering, and serves to stabilize deep electric field levels.

〔Example〕

The present invention will now be described in detail with reference to FIGS. 1 and 2.

FIG. 1 is a cross-sectional view showing the structure of an EL panel according to the present invention. In the figure, 11 is a glass substrate, 12 and 13 are transparent electrodes and a first insulating layer that are sequentially formed on the substrate 11. On the first insulating layer 13, there is a light emitting layer 14 and a ZnSe intermediate layer 15 that does not contain a light emitting center impurity (the amount of impurity is controlled).
and an oxide insulator intermediate layer 16, a second insulating layer 17,
Back electrodes 18 are sequentially formed to form an EL panel.

Luminescent layer 14. Zn5e intermediate layer 15. The procedure for forming the oxide insulator intermediate layer 16 is as follows.

The light emitting layer 14 is formed by vacuum deposition and contains a large amount of light emitting center impurities. On the light emitting layer 14, a thin Zn Se intermediate layer 15 containing no emission center impurity is formed by vacuum evaporation, and thereon a thin oxide insulator intermediate layer 16 is formed by sputtering. A second insulating layer 17 is subsequently formed on this oxide insulating intermediate layer 16.

Zn Se intermediate layer 15. The role played by the oxide insulator intermediate layer 16 is as follows.

The light-emitting layer 14 contains a large amount of light-emitting center impurities as described above, and there is a deviation from the crystal stochiometry and disordered crystallinity, and in addition, other impurities are included in the light-emitting impurities. Therefore, as shown in FIG. 2, many electronic levels are created between the band gaps of ZnS. On the other hand, Zn
Since the Se intermediate layer 15 does not contain luminescent center impurities,
It serves to eliminate unnecessary electronic levels at the interface between the light emitting layer 14 and the second insulating layer 17. Further, since the impurity amount of ZnSe, which is the material of the ZnSe intermediate layer 15, can be controlled more easily than ZnS, the electronic level between the light emitting layer 14 and the second insulating layer 17 can be artificially controlled. Furthermore, the oxide insulator intermediate layer 16 formed by sputtering plays a role in stabilizing deep interface states. This can be confirmed from the fact that the rising voltage VlfL of the luminance-voltage characteristic of the EL panel becomes higher as shown in Table 1 below. It is thought that the shallow interface states are filled by the influence of oxygen in the oxide insulator.

Table 1 [Effects of the Invention] As described above, according to the present invention, the following various excellent effects can be achieved.

(1) It is possible to stabilize the electronic level near the interface of the light-emitting layer of the EL panel, thereby stabilizing the light-emitting characteristics.

(2) The electronic level between the light emitting layer and the second insulating layer can be easily controlled artificially.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of an EL panel according to an embodiment of the present invention, FIG. 2 is an explanatory view of the operation of the EL panel according to the present invention, and FIG. Inside, 12 is a transparent electrode, 13 is a first insulating layer, 14 is a light emitting layer, 15 is a ZnSe intermediate layer, 16 is an oxide insulator intermediate layer, 17 is a second insulating layer, and 18 is a back electrode.

Claims (1)

[Scope of Claims] An EL panel in which a transparent electrode is formed on one surface of a light-emitting layer through a first insulating layer, and a back electrode is formed on the other surface through a second insulating layer, wherein the light-emitting layer and the A structure of an EL panel characterized in that a Zn Se intermediate layer containing no emission center impurity and an oxide insulator intermediate layer are formed in order from the light emitting layer side between the second insulating layer and the second insulating layer.