JPH03283294A - Thin film electroluminescence device - Google Patents

Abstract

PURPOSE:To limit a luminous area and prevent the crosstalk phenomenon between luminous picture elements and enhance the contrast of display by constituting a light- emitting layer of divided luminous portions ln the form corresponding to electrode structure. CONSTITUTION:An ITO layer is formed on a glass base 1 and is patterned in the shape of stripes to form divided transparent electrode portions 2a, 2b... and is coated with silicon nitride to form a first insulating layer 3. A light-emitting layer 4 is formed from zinc sulfide containing manganese by 0.5wt%. A resistration 7 is formed on the picture element predetermined area of the light emitting layer 4 to form divided luminous portions 4a, 4b.... Thereafter, the resistration 7 is removed and the layer 4 is coated with silicon nitride to form a second insulating layer 5 and further divided Al electrode portions 6a, 6b... are formed thereon. The superimposed area of the plane of projection of each divided transparent electrode portion and each divided Al electrode portion both of which cross each other serves as luminous picture elements, but since the divided luminous portions are limited to the superimposed area, the portion around the superimposed area does not emit light and the divided luminous portions are surrounded by the second insulating layer so expansion of an electric flux outside the superimposed area is decreased.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a thin film electroluminescent device used as a thin display device, and particularly relates to the structure of a double insulated thin film electroluminescent device having a plurality of light emitting pixels. It is something.

[Conventional technology]

Thin-film electroluminescent devices (hereinafter referred to as thin-film EL devices) that exhibit a light-emitting phenomenon when an electric field is applied are attracting attention as light-emitting panels for thin display devices because of their high luminance, high resolution, and large display capacity. .

In the conventional thin film EL device, as shown in FIG. 3, a transparent electrode 12 made of ITO (In-5n-0) is formed on a glass substrate 11, and silicon nitride (S
The first insulating layer 13 is made of zinc sulfide (Z
A light-emitting layer 14 in which a transition metal such as manganese (Mn) or a rare earth element such as terbium (T b ) is added as a luminescent center in nS), and a second insulating layer 15 made of silicon nitride or the like are sequentially laminated. Above the Af electrode 16
It has a structure in which it is coated with

Here, both the transparent electrode 12 and the A°C electrode 16 are connected to the fourth
As shown in the figure, a plurality of striped open transparent electrode portions 12a, 12b, . . . and division A! Electrode part 16a
, 16b, ..., which are:
They extend in directions perpendicular to each other. By forming such a structure, the divided transparent electrode parts 12a, 12b,
...and split A! Electrode parts 16a, 16b,...
When the planar shape of * is projected onto the light-emitting layer 14, areas of the light-emitting layer 14 where these projected images intersect and overlap selectively emit light, so these overlapping parts can be used as light-emitting pixels to configure a display body. I can do it.

[Problem B to be Solved by the Invention] However, in the above-mentioned conventional thin EL device, even if an attempt is made to selectively cause a specific light-emitting pixel to emit light, an electric field is also applied around the light-emitting pixel, so that the light-emitting area is A crosstalk phenomenon occurs that spreads continuously and is not clearly defined, and in extreme cases, the light emitted even extends to the area of adjacent pixels.
There was a problem in that display contrast was reduced.

In addition, in order to reduce this crosstalk phenomenon, the divided transparent electrode portions 12a, 12b, ... and the divided Af
When forming the electrode portions 16a, 16b, . . . , it is necessary to provide a large distance between adjacent electrode portions.
There was a problem in that the density of the light-emitting pixels decreased, making it impossible to form a high-density image.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and its object is to provide a thin film EL device capable of high-density display by preventing the crosstalk phenomenon by limiting the light emitting area of the light emitting device [14]. There is a particular thing.

[Means for Solving the Problems] In order to solve the above problems, the means taken by the present invention are as follows:
The light-emitting layer is composed of a plurality of divided light-emitting parts, and these divided light-emitting parts are selectively formed in the overlapping region of the projected plane image of the transparent electrode and the projected plane image of the back electrode.

[Effect]

According to this means, since the divided light emitting parts are selectively formed in the 4N overlap region of the projected images of the transparent electrode and the back electrode that face each other, the light emitting area is limited to the area where the divided light emitting parts are formed, and the divided light emitting parts are As a matter of course, areas where no part is formed do not emit light.

In this way, since the light emitting region is limited by the divided light emitting sections, crosstalk phenomenon can be prevented and display contrast can be improved. As a result, the light-emitting pixels can be arranged with high density, so it is possible to manufacture a display body that can form images with high density.

[Example] Next, the present invention will be described in detail with reference to the drawings.

FIGS. 1(a) to 1(d) show the manufacturing process of a thin EL device according to an embodiment of the present invention. An ITO layer with a thickness of 2,000 layers was formed on the glass substrate 1 by sputtering, and patterned into stripes by wet etching to form divided transparent electrode parts 2a, 2b, . . .
A first insulating layer 3 with a thickness of 3,000 layers is formed by depositing silicon nitride on this layer by sputtering (
Figure 1(a)). Next, zinc sulfide containing Q, 5 wt% of manganese was used as a material, and a film thickness of 5000 was made by electron beam evaporation.
A human light emitting layer 4 is formed (FIG. 1(b)). A resist 7 is formed on the pixel constant area of the light emitting layer 4 by a photo process.
Using this resist 7 as a mask, dry etching is performed using a mixed gas of methanol and argon to form divided light emitting sections 4a, 4b, . . . (FIG. 1(C)). Thereafter, the resist 7 was removed and silicon nitride was deposited by sputtering to a film thickness of 3000.
A second insulating layer 5 is formed, and a film thickness of 50
One layer of OA is deposited by sputtering, sealed in the divided transparent electrode parts 2a, 2b, etc., and patterned into a stripe shape extending in orthogonal directions.
f electrode parts 6a, 6b, . . . are formed (FIG. 1(d))
).

In the thin film EL device thus formed, the divided transparent electrode portions 2a and 2b are orthogonal to each other.

... and the divided A2 electrode parts 6a, 6b, .
4b, . . . are limited to the overlapping region, the area around the overlapping area does not emit light, and the surrounding area is surrounded by the second insulating layer made of silicon nitride with a low dielectric constant, so
Compared to the case where an integral light emitting layer 4 is formed, the overhang of electric flux outside the overlapping region is reduced. Therefore, the area to which the high electric field required for light emission is applied is more limited than before.
The display contrast is improved without the occurrence of cocoon talk. This makes it possible to arrange light-emitting pixels at a higher density than in the past, enabling high-density display.

In the above embodiment, the emitted light N4 was selectively etched away to form the divided light emitting parts 4a, 4b, . . . , but as shown in FIG. The divided light emitting portions 4a, 4 are formed in a single step by vapor deposition while restricting the vapor flow 10 through a metal mask 8 having an opening corresponding to the intended pixel area between the source 9 and the source 9.
b, . . . can also be formed.

[Effects of the Invention] As explained above, the present invention is characterized in that the light-emitting layer is composed of divided light-emitting parts each having a shape corresponding to the electrode structure, so that the light-emitting area is limited and crosstalk between light-emitting pixels is reduced. Since this phenomenon is also prevented, display contrast is improved. Furthermore, as a result, the light emitting pixels can be arranged in a high density arrangement, and high density display is possible.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(d) show thin film ELs of examples according to the present invention.
FIG. 3 is a process cross-sectional view showing the manufacturing process and structure of the device. FIG. 2 is a conceptual diagram showing a method of forming a divided light emitting section using a metal mask. FIG. 3 is a longitudinal sectional view showing the structure of a conventional thin film EL device. FIG. 4 is a perspective view showing the structure of a conventional thin film EL device. [Explanation of symbols] 1...Glass substrates 2a, 2b,...Divided transparent electrode portion 3...
First insulating layer 4...Light emitting layers 4a, 4b,...Divided light emitting section 5...Second
Insulating layers 6a, 6b...divided Al electrode 7...resist 8...metal mask 9...evaporation source 0...vapor flow. ] Figure 2 Figure 2 Figure Transparent electrode Figure

Claims (1)

[Claims] In a thin film electroluminescent device having a structure in which at least a transparent electrode, a first insulating layer, a light emitting layer, a second insulating layer, and a back electrode are sequentially stacked, at least one of the transparent electrode and the back electrode is formed of a plurality of divided electrodes. The light-emitting layer is composed of a plurality of divided light-emitting parts formed only in an overlapping area of the projected plane image of the transparent electrode and the projected plane image of the back electrode. Thin film electroluminescence device.