JPH0740516B2 - Flat display device and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a flat display device with high contrast and a manufacturing method thereof.

[Technical background of the invention]

Conventionally, various kinds of flat panel display devices have been used, but most of them include a transparent electrode and a metal electrode facing the transparent electrode as constituent elements. Conventionally, the flat display device of this type has the following problems. An electroluminescent (EL) flat panel display, which is a typical surface display, will be described below as an example.

FIG. 1 shows a cross-sectional structure of an electroluminescent (EL) flat panel display device, 1 is a glass substrate, 2 is a transparent electrode, 3 is an EL light emitting source, 4 is an insulating film, and 5 is a metal electrode.
In this type of flat display device, normally, ZnS added with Mn, Tb, etc. is used as the EL light emitting source 3 and SmO ₃ etc. is used as the insulating film, but these films are highly transparent to visible light. Have sex. Further, Al having a high reflectance is most commonly used as the metal electrode 5. As a result of using these materials in combination, most of the light that is incident on the flat panel display device from the outside is reflected by the metal electrode 5, and there is a drawback in that the contrast of the flat panel display device is reduced.

In order to solve such a problem, a flat panel display device having a sectional structure as shown in FIG. 2 has been proposed.

That is, Mo is present between the metal electrode 5 made of Al and the insulating film 4.
It has a structure in which the film 6 and the Al ₂ O ₃ film 7 are arranged (Miwa et al., 32nd Joint Lecture on Applied Physics, Lecture Proceeding, Lecture No. 1p-Y-8).

In this flat display device, the film subsequent to Mo / Al ₂ O ₃ acts as a kind of antireflection film and suppresses the reflection of external light by the metal electrode 5. However, in this flat display device, since the Al ₂ O ₃ film 7 which is an insulator is arranged between the Mo film 6 and the metal electrode made of Al, the metal electrode 5 and the transparent electrode 2 are
When a voltage is applied between the _two , a voltage drop occurs in the Al ₂ O ₃ film 7. Therefore, in order to apply the same voltage to the EL light emitting film 3 as in the case of the flat panel display device having the structure shown in FIG.
There is a drawback that a higher voltage must be applied from the outside.

Further, in order to eliminate this problem, the metal electrode 5 and the Mo film 6 must have the same potential. Therefore, in order to realize a practical flat display device, a contact hole is formed in the Al ₂ O ₃ film, It is necessary to electrically connect the metal electrode 5 and the Mo film 6. This has a drawback in that the manufacture of the flat panel display device is considerably complicated, and a decrease in manufacturing yield and an increase in manufacturing cost cannot be avoided.

[Outline of Invention]

The present invention has been made in view of the above points, and provides a flat display device and a manufacturing method thereof, which have a higher contrast than conventional flat display devices, do not complicate the manufacturing, and can reduce the manufacturing cost. The purpose is to do.

Therefore, the flat panel display device according to the present invention is a flat panel display device in which a light emitting film is provided between a transparent electrode and a counter electrode, and light is emitted by applying a voltage to the transparent electrode and the counter electrode tube. The electrode is characterized by using a MoO ₂ film at least in part.

Further, the method for manufacturing a flat panel display device according to the present invention is a method for manufacturing a flat panel display device in which a light emitting film is formed between opposing electrodes using a transparent electrode and a MoO ₂ film as at least a part,
The O ₂ film is formed by reactive sputtering in a sputtering gas containing O ₂ .

Further, according to the second manufacturing method of the flat display device according to the present invention, a method of manufacturing a flat display device in which a light emitting film is formed between the counter electrodes using the transparent electrode and the MoO ₂ film at least in part, The MoO ₂ film is formed by reducing the _Mo O ₃ film.

According to the flat panel display device of the present invention, MoO ₂ having high conductivity as an electrode or a part of the electrode that absorbs visible light is used.
Since the film is used, there is an advantage that it has high contrast. Further, according to the flat panel display device of the present invention, the antireflection film Al is formed between the counter electrode and the transparent electrode.
Since it is not necessary to form an insulating film such as a ₂ O ₃ film, there is an advantage that the conductivity between the electrodes is not taken into consideration, the manufacturing is remarkably simple, and the cost is significantly reduced.

[Specific Description of the Invention]

Embodiment 1 FIG. 3 is a sectional view for explaining the first embodiment of the flat panel display device of the present invention, in which 1 is a glass substrate, 2 is a transparent electrode, 3 is an EL light emitting source, and 4 is an insulation. Membrane, 8 is a MoO ₂ membrane electrode.

In such a flat panel display device, as is apparent from FIG. 3, a transparent electrode 2 is laminated on a transparent substrate 1 such as glass, a light emitting film 3 is provided on the transparent electrode 2, and an insulating film 4 is further provided. The MoO ₂ film 8 is formed through the structure.
In this embodiment, the MoO ₂ film 8 is formed as shown in FIGS.
It is the electrode 5 in the figure.

The transparent electrode 2 as described above may be basically any one in the present invention, and, for example, one conventionally used as this type of transparent electrode can be effectively used.
Further, the light emitting film 3 laminated on the transparent electrode 2 may basically be any one as long as it emits light by applying a voltage between the MoO ₂ film electrode 8 and the transparent electrode 2. For example, it can be an EL light emitting film using a ZnS film added with Mn, Tb, or the like.

Further, the insulating film 4 laminated on the light emitting film 3 is basically not limited in the present invention. The insulating film used in the conventional flat display device of this type can be effectively used. For example, it can be the aforementioned Sm ₂ O ₃ film.

The MoO ₂ film 8 laminated on the insulating film 4 has a brown or black color as described in the literature (for example, “Science Dictionary”, 3rd edition, Iwanami Shoten, 1977). Yes, it has high conductivity. Therefore, most of the light incident on the flat panel display device from the outside is absorbed by the MoO ₂ film 8. Also since MoO ₂ film 8 is a good conductor of electricity, MoO ₂
The film 8 has the same function as that of the metal electrode 5 which has been generally used conventionally as described in FIG. 1, that is, functions as an electrode. As described above, according to the flat panel display device of the first embodiment of the present invention, it is possible to reduce the reflection of external light from the electrodes despite the extremely simple structure, and as a result, the contrast of the flat panel display device is significantly improved. Can be made.

Embodiment 2 FIG. 4 is a second embodiment of the flat display device according to the present invention, in which a metal electrode 5 is further formed on the MoO ₂ film 8 electrode of the flat display device of the first embodiment. That is, the electrode is Mo
It has a structure in which the metal electrode 5 is laminated on the O ₂ film electrode 8.

The metal electrode 5 laminated on such a MoO ₂ film 8 is not basically limited in the present invention, and is, for example, an electrode made of Al, Mo, etc. which has been conventionally used as this kind of electrode. You can Since metals such as Al and Mo are easily bonded to a metal electric wire, the flat display device having the structure shown in FIG. 4 can be used to connect the electrodes and the electric wires with high yield. In addition, since a metal such as Al having a low electric resistance can be selected as a material of the metal electrode 5, the low resistance of the electrode, which is required when manufacturing a flat display device having a large number of scanning lines, can be satisfied. it can.

Next, a method of manufacturing the flat panel display device according to the present invention will be described.

Example 3 According to the method of manufacturing the flat panel display device of the present invention, the transparent electrode 2, the light emitting film 3, and the insulating film 4 are sequentially formed on the transparent substrate 1 such as glass. As a method of forming such a transparent electrode 2 or the like, the method of forming conventionally used in this type of technique can be effectively used.

After forming the insulating film 4 as described above, according to the first method of the present invention, the MoO ₂ film 8 is reacted in a sputtering gas containing O ₂ by using an RF magnetron sputtering device or the like. It is formed by spattering. At this time, Mo is used as the sputtering target and a mixed gas of O ₂ and an inert gas such as Ar is used as the sputtering gas.

The flow rate ratio of such an inert gas and oxygen is preferably
It should be between 5: 5 and 9: 1. If it deviates from this range, the film may not be formed well.

The gas pressure at the time of sputtering is preferably 1 to 5 Pa. If the gas pressure is less than 1 Pa, the discharge of the spattering may become unstable, and if it exceeds 5 Pa, the discharge of the spattering may become unstable.

The MoO ₂ film can be deposited by performing the reactive sputtering under the above conditions. Then, electrodes are processed by photolithography to manufacture a flat display device having the structure shown in FIG.

It is also possible to optionally stack the metal electrode 5 on such a MoO ₂ film to manufacture the flat display device having the structure shown in FIG.

Example 4 In the second example of the method according to the present invention, the transparent electrode 2, the light emitting film 3, and the insulating film 4 were sequentially laminated on the substrate 1, and then the MoO ₃ film was formed on the insulating film 4. Form. The method of forming such a MoO ₃ film is not limited in the present invention. For example, a Mo film is formed by a method such as vacuum deposition, a CVD method, or a sputtering method, and then the Mo film is oxidized, for example, in an O ₂ atmosphere at about 400 ° C.
Film can be formed MoO ₃ film is changed to a MoO ₃ film.

Next, the MoO ₃ film is reduced to form a MoO ₂ film, but such a reduction method is not limited in the present invention, and, for example, in a reducing gas atmosphere, preferably 300 to 400 ° C. MoO ₃ can be reduced to MoO ₂ film at the temperature of. Examples of the reducing gas as described above include H ₂ or
And H ₂ -N ₂ gas can be cited as examples.

Further, if the reduction temperature is lower than 300 ° C, the reduction may not be performed well, while if it exceeds 400 ° C, a side reaction may occur.

In such reduction, the MoO ₃ film is reduced to the MoO ₂ film according to the following formula.

MoO ₃ + H ₂ → MoO ₂ + H ₂ O Then, the electrodes are processed by photolithography, and the third
The flat display device having the structure shown in the figure is manufactured.

It is also possible to optionally stack the metal electrode 5 on such a MoO ₃ film to manufacture the flat display device having the structure shown in FIG.

In the above embodiments, an electroluminescent (EL) flat panel display device has been mainly described, but the present invention provides an electrode with less reflection of external light and a manufacturing method thereof. It is obvious that the present invention can be applied to a target flat display device, particularly a light emitting flat display device.

〔The invention's effect〕

As described above, according to the flat panel display device of the present invention, there is an advantage that a flat panel display device having a simple structure and high contrast can be provided. Further, according to the method of manufacturing the flat panel display device of the present invention, there is an advantage that the above flat panel display device can be manufactured with high yield and at low cost. Moreover, when applied to flat display devices for various information equipment terminals having remarkable versatility, the above advantages can be effectively utilized.

[Brief description of drawings]

FIG. 1 is a sectional view of an example of a conventional flat panel display device, FIG. 2 is a sectional view of a second example of a conventional flat panel display device, and FIG. 3 is a first embodiment of a flat panel display device according to the present invention. FIG. 4 is a sectional view of a flat display device according to a second embodiment of the present invention. 1 ... Substrate, 2 ... Transparent electrode, 3 ... Light emitting film, 4 ... Insulating film, 5
... Metal electrode, 6 ... Mo film, 7 ... Al ₂ O ₃ film, 8 ... MoO ₂ film.

Claims (3)

[Claims] 1. A flat display device in which a light emitting film is provided between a transparent electrode and a counter electrode, and a voltage is applied between the transparent electrode and the counter electrode so that the flat display device emits light, the counter electrode is a MoO ₂ film. A flat panel display device characterized by using at least a part of. 2. A method of manufacturing a flat panel display device comprising a transparent electrode and a MoO ₂ film at least a part of which a light emitting film is formed between opposed electrodes, wherein the MoO ₂ film is formed in a sputtering gas containing O _2. A method of manufacturing a flat panel display device, which is formed by reactive sputtering. 3. A method of manufacturing a flat panel display device comprising a transparent electrode and a MoO ₂ film at least a part of which a light emitting film is formed between opposed electrodes, wherein the MoO ₂ film is formed by reducing the MoO ₃ film. A method for manufacturing a flat display device, which comprises: