JPS6250958B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electroluminescent display element (hereinafter abbreviated as "EL display element") that emits light upon application of a voltage, and particularly to an electroluminescent display element (hereinafter abbreviated as "EL display element") that emits multicolor light with a single luminescent matrix layer. The present invention relates to a method for manufacturing an EL display element that can be obtained.

Electroluminescent development is available in London, Edinburgh and Dublin Philosophical Magazine (London.
Edinburgh and Doublin Phylosophical
It was first published in an early paper by G. Destriau that appeared in Series 7, Volume 38, No. 285, pages 700-737 (October 1947). Since then, considerable research and technical effort has been expended, and various devices based on this have already been put on the market.

Recently, it has become possible to display multi-colored luminescence.
EL display elements have been proposed, for example,
In Publication No. 54-29318, a vapor-deposited film containing a rare earth element fluoride is made in a luminescent matrix of ZnS, and a metal manganese vapor-deposited film in an arbitrary shape is sandwiched on or inside the film, and the film is diffused by heat treatment. The part of the figure emits red EL (700Å), and the other parts emit light from rare earth elements.For example, yellow for DyF ₃ , green for TbF ₃ and ErF ₃ , and blue for TmF ₃ .
A thin film EL display element that emits light and enables two-color electroluminescence with a single ZnS thin film has been disclosed.

However, EL display elements manufactured using this method are manufactured by forming a multilayer vapor-deposited film in which 1 to 3 thin metal manganese layers with a desired pattern are sandwiched between a ZnS film mixed with TbF ₃ , for example, and then depositing about 600
℃ for 3 hours to diffuse manganese into the ZnS film, so there are regions in which only TbF ₃ is added to ZnS and regions in which TbF ₃ and Mn are added and both form a composite center. The disadvantage is that it is difficult to see the boundaries clearly, and it is difficult to obtain a sharp display due to so-called "bleeding" when emitting light, which is particularly limiting for shapes that display fine patterns such as dot matrix patterns. There is,
The drawback is that the display pixel size is limited to about 200 μs in both the vertical and horizontal directions, which limits the scope of its practical use.

The present invention has been made in view of the above-mentioned drawbacks, and is particularly easy to manufacture and allows various characters, numbers, images, etc. to emit extremely sharp light, as well as displaying fine patterns. The purpose of the present invention is to provide a method for producing a novel EL display element that can be manufactured using the following methods.

That is, in the EL display element according to the present invention, multiple types of rare earth metal ions are individually implanted as luminescent centers into the luminescent matrix layer by ion implantation, and at this time, photoresist is used as a mask material to implant the ions into the luminescent matrix layer. By defining the region of rare earth metal ions and obtaining a luminescent center layer with a predetermined pattern,
The present invention is intended to obtain multicolor electroluminescence with a single light-emitting host layer, and the present invention will be explained in detail with reference to Examples below.

1 to 6 are diagrams showing the manufacturing process of an EL display element according to the present invention, in which a transparent electrode 2 made of In ₂ O ₃ , SnO ₂ , etc. is placed on a transparent insulating substrate 1 made of a glass substrate or the like. , a first dielectric layer 3 made of V ₂ O ₃ , etc., and a luminescent matrix layer 4 made of ZnS, etc., are sequentially deposited in this order by vacuum evaporation so that the film thicknesses are about 2000 Å, about 3000 Å, and about 3000 to about 6000 Å. Laminated layers are formed (see Figure 1).

A photoresist 5a is coated on the luminescent matrix layer 4, and the photoresist 5a in the portion where the first luminescent center is injected is removed by exposure to ultraviolet rays or electron beam phosphorography and immersion in a phenomenon liquid. , Tb ³⁺ is injected into the luminescent base layer 4 by ion implantation to form the first luminescent center layer 6a.
(See Figure 2).

After forming the first luminescent center layer 6a, the previous photoresist 5a is dissolved and removed, and another photoresist 5b is applied.
, and remove the photoresist 5b in the area where the second luminescent center is to be injected by the same method as above,
Sm ³⁺ is injected into the luminescent base layer 4 by ion implantation to form the second luminescent center layer 6b (third
(see figure).

After forming the second luminescent center layer 6b, the previous photoresist 5b is dissolved and removed, and another photoresist 5c is applied.
, and remove the photoresist 5c in the part where the third luminescent center is to be injected by the same method as above,
Tm ³⁺ is injected into the luminescent base layer 4 by ion implantation to form a third luminescent center layer 6c (see FIG. 4).

After forming the third luminescent center layer 6c, the photoresist 5c is dissolved and removed, and then annealing is performed in vacuum to about 500° C. and baked for about 30 minutes in order to compensate for crystal defects (see FIG. 5).

On top of this, a second dielectric layer 7 made of V ₂ O ₃ or the like and a reflective metal back electrode 8 made of Al or the like are sequentially laminated in this order by vacuum evaporation so that each film has a thickness of about 3000 Å. By doing so, an EL display element is manufactured (see FIG. 6).

The EL display element formed in this way has electrodes 2,
By applying a voltage across 8, the interface between the luminescent matrix 4 and each luminescent center 6a, 6b, 6c emits light,
As the voltage increases, the entire luminescent centers 6a, 6b, and 6c emit light uniformly, with the first luminescent central layer 6a region being green, the second luminescent central layer 6b region being blue, and the third luminescent central layer 6b being blue. The central layer 6c area emits red light (see FIG. 7).

In addition, each luminescent center layer 6a, 6b, 6c is provided so as to form a predetermined area by masking using photoresists 5a, 5b, 5c, so that it can be formed in a more complicated shape or with fine dimensions compared to conventional manufacturing methods. Can be made with high precision and "bleed"
It is easy to obtain a sharp display without any blemishes.

Then, the electrodes 2 and 8 are each formed into a rectangular shape and are formed so as to be perpendicular to each other with the light emitting matrix layer 4 in between.
By selecting the applied voltage to each electrode 2, 8, each light emitting center 6
It is also possible to cause the a, 6b, and 6c areas to emit light individually, and it is also possible to display complex color changes using a fine dot matrix with display pixel dimensions of about several tens of micrometers both vertically and horizontally (see Figure 8). .

As described above, according to the present invention, a plurality of rare earth metal ions are individually implanted into a light-emitting matrix layer provided in advance by masking with a photoresist so as to have a predetermined shape area, thereby forming a single phosphor layer. Multi-color electroluminescence is possible with the luminescent matrix layer, and in particular, a vapor deposited film containing rare earth element fluoride is created in the luminescent matrix of ZnS, and then a metallic manganese vapor deposited film in an arbitrary shape is sandwiched on or inside it. Although the structure is similar at first glance, the manufacturing method is completely different from the conventional example, which uses diffusion through heat treatment to make the emitted light color different between parts of the figure and other parts, and has effects that cannot be obtained with the conventional example.
In other words, sharp displays and numbers without “bleeding”
A fine display shape with dimensions of about 10 μm can be obtained.

In addition, compared to multilayer EL display elements that emit multicolor light by sandwiching multiple types of light-emitting base layers containing different types of light-emitting centers between insulating layers and transparent electrodes, the number of insulating layers and transparent electrodes The structure is simple because of the small number of elements, and the overall thickness of the EL display element is also small.

In addition, we have developed a separate single-layer EL display in which multiple types of light-emitting base layers containing different types of light-emitting centers are separated in a plane using a vacuum evaporation method using a mask to obtain multicolor light emission. In the element, the minimum value of the gap between the luminescent base layers separated by mask vapor deposition is as large as about 200 μm, and compared to this, the EL display element according to the present invention has the advantage of being able to obtain a fine pattern of luminescent shape. .

Moreover, since photoresist is used as the mask material, there is no need for expensive jigs or molds, and the mechanical and chemical properties of the material are not changed, allowing even complex shapes and minute dimensions to be obtained with high precision. This has the advantage of being extremely practical in that design changes can be easily made.

[Brief explanation of the drawing]

1 to 6 are cross-sectional views illustrating the manufacturing method of an embodiment of an EL display element according to the present invention, and FIG.
FIG. 8 is a schematic plan view illustrating a light emitting display state of the EL display element same as the above. FIG. 1: Substrate, 2: Transparent electrode, 3, 7: Insulating layer,
4: Luminescent base layer, 5a, 5b, 5c: Photoresist, 6a, 6b, 6c: Luminescent center layer, 8: Back electrode.

Claims (1)

[Scope of Claims] 1. In an electroluminescent display element having a double insulating layer structure which is sandwiched between an insulator and an electrode and emits light by applying a voltage to the electrode, after forming a luminescent base layer, A plurality of types of rare earth metal ions are individually implanted as luminescent centers into the luminescent matrix layer by an ion implantation method, and at this time, a photoresist is used as a mask material to define a region of the rare earth metal ions to be implanted into the luminescent matrix layer. 1. An electroluminescent display element characterized in that it obtains multicolor electroluminescence by obtaining a luminescent center layer with a predetermined pattern.