JP3473306B2 - Thin film display element and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a structure in which a voltage is applied to a conductive layer and a conductive thin film in a vacuum so that electrons generated from the insulating thin film penetrate the conductive thin film and are arranged on the side opposite to the insulating thin film. The present invention relates to a thin film display device for irradiating a fluorescent plate and a method for manufacturing the same. This thin film display element is currently being developed for electronic display devices such as notebook computers and thin-screen televisions. The electrons generated from the thin film display element cause the fluorescent plate to emit light, and characters and figures are displayed on the fluorescent plate. Can be displayed.

[0002]

2. Description of the Related Art Liquid crystal display elements and electroluminescent elements (EL elements) are generally used as display elements used in electronic display devices. However, since the liquid crystal display element is not a self-luminous type, it requires a backlight, and has a problem that the power source capacity is large. Further, the EL element requires a driving voltage of several hundreds of volts, which is a drawback that the driving voltage is high. Recently, a field emission type display device using plasma has been proposed, but the drive voltage of this display device is also as high as several hundred volts to 1 kV.

As a self-luminous display device having a low driving voltage (about 10 V), a thin film display device in which a conductive thin film is formed on the surface of a conductive layer via an insulating thin film has been developed. When a voltage is applied to the conductive layer and the conductive thin film in vacuum, electrons generated from the insulating thin film penetrate the conductive thin film due to the tunnel effect and come out of the thin film display element. By receiving the generated electrons by the fluorescent plate, the fluorescent plate can be caused to emit light to display characters and figures.

FIG. 6 is a sectional view showing the structure of a conventional thin film display element. A conductive layer 17 made of aluminum is disposed on an insulating substrate 16 such as ceramic, and an insulating thin film 18 of alumina formed by oxidation of aluminum is formed on the upper surface of the conductive layer 17, and gold is vapor-deposited on the insulating thin film 18. The conductive thin film 19 made of is formed. Insulating substrate 16
To the conductive thin film 19 is a thin film display element 20. The thin film display element 20 is housed in a vacuum, and a fluorescent plate 15 (shown by a dotted line) is placed on top of it to be used for an electronic display device.

The insulating thin film 18 has a thickness of 2 to 3 nm, and the conductive thin film 19 has a thickness of tens to hundreds of nm. By applying a direct current voltage of about 10 V between the conductive layer 17 and the conductive thin film 19, the electrons excited from the insulating thin film 18 penetrate the conductive thin film 19 by the tunnel effect. This electron travels as shown by arrow 19A and reaches the upper fluorescent plate 15. Fluorescent plate 15 illuminated by electrons
Emits light, so that characters and figures can be displayed by arranging a large number of thin film display elements 20 on a plane.

[0006]

However, the conventional thin film display device as described above has a problem that the insulating thin film is easily cracked during manufacturing. That is, since the thickness of the insulating thin film needs to be very thin, such as several nm, the strength of the insulating thin film is low and cracks are likely to occur after the conductive layer is oxidized. Therefore, the generation of electrons is not stable and cracks increase with time, so that the life is short.

Further, a plurality of metals such as gold and aluminum are required for the film formation, and there is a trouble that the separation treatment is required when the element is discarded as an environmental measure. An object of the present invention is to provide a thin film display element which is composed of a single atom and which is free from cracks.

[0008]

In order to achieve the above object, according to the present invention, an insulating thin film is formed on the surface of a conductive layer, and the conductive thin film is formed on the surface of the insulating thin film on the side opposite to the conductive layer. In the thin film display element formed as described above, it is preferable that the conductive layer, the insulating thin film and the conductive thin film are all composed of carbon atoms. As a result, the thin film display element can be composed of a single atom of carbon, and a separation process when discarding is unnecessary.

Further, in such a structure, the conductive layer may be made of carbon having a graphite structure, the insulating thin film may be made of carbon having a diamond structure, and the conductive thin film may be made of carbon having a pseudo one-dimensional structure. As a result, the strength of the insulating thin film becomes very large, and the insulating thin film does not crack.
Further, in a method of manufacturing a thin film display element having such a structure, carbon vapor generated from a graphite material by laser light irradiation is deposited on a conductive layer to form an insulating thin film, and the insulating thin film is coated with a graphite electrode pair. The conductive thin film may be formed by irradiating a pinch plasma generated between the conductive thin films.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on embodiments. FIG. 1 is a sectional view showing the structure of a thin film display element according to an embodiment of the present invention. An insulating thin film 2 made of carbon having a diamond structure is formed on the upper surface of a conductive layer 1 made of carbon having a graphite structure, and a conductive thin film 3 made of carbon having a pseudo one-dimensional structure is formed on the upper surface of the insulating thin film 2. This thin film display element is housed in a vacuum, and a fluorescent plate (not shown) is placed on top of it to be used in an electronic display device.

The insulating thin film 2 has a thickness of 2 to 3 nm, and the conductive thin film 3 has a thickness of several tens nm to several hundreds nm. As in the conventional thin film display element, by applying a direct current voltage of about 10 V between the conductive layer 1 and the conductive thin film 3, electrons excited from the insulating thin film 2 penetrate the conductive thin film 3 by the tunnel effect. Irradiate a fluorescent plate (not shown) on the upper side.

Next, each structure of the carbon atom described in FIG. 1 will be touched upon. FIG. 3 is a perspective view showing a carbon bond of a graphite structure. Ring 40 having a regular hexagonal carbon atom 4
And the ring 40 is infinitely connected on the plane to form one layer 4A. The layers 4A are formed in parallel and innumerably, and are bonded to each other. The bond 41 (solid line) that the carbon atom 4 forms the ring 40 is a covalent bond and is quite strong.
However, the bond 42 (dotted line) of each layer 4A is an intermolecular force and is relatively weak. Therefore, each layer 4A is mutually
It has a property that it is easy to slip in a direction parallel to and each layer 4A is thin and easily peeled off.

FIG. 4 is a perspective view showing a carbon bond of a diamond structure. The carbon atom 4 is at the center of the tetrahedron 4B,
They are arranged innumerable by covalent bonds while maintaining the positional relationship as at the four vertices. Which carbon atom 4
Is also strongly connected by covalent bonds, so its strength is extremely high. FIG. 5 is a diagram showing a carbon bond having a quasi one-dimensional structure, (A) is a side view of a main part, and (B) is a plan view of the main part.
In FIG. 5A, carbon atoms 4 are connected in one direction to form a carbon chain 4C. In FIG. 5B, the carbon chain 4
The Cs are aligned perpendicular to the six sides. The carbon chains 4C are connected to each other via bonds 43 in places. This structure is called a quasi-one-dimensional structure because the carbon atoms 4 arranged in one direction are bundled.

As described above, since the insulating thin film 2 has a diamond structure and is very strong, cracks do not occur even if the insulating thin film 2 is as thin as several nm. Therefore, the generation of electrons from the insulating thin film 2 is stabilized and the life thereof is extended. Moreover, since all of them are composed of a single element of carbon atoms 4, there is no need to separate them when disposing of the device. next,
A method of manufacturing the thin film display element of FIG. 1 will be described.

FIG. 2 is a sectional view showing an apparatus for manufacturing the thin film display element of FIG. A flat plate electrode 6 is arranged inside the vacuum container 7, and a counter electrode 10 having a gas passage 11 is arranged so as to face the flat plate electrode 6. Both the plate electrode 6 and the counter electrode 10 are made of graphite. The gas passage 11 has a cylindrical lower opening. On the other hand, the upper opening of the gas passage 11 is integrated into one and communicates with the gas supply unit 9 provided outside the vacuum container 7. A laser oscillator 5 is arranged outside the vacuum container 7. The laser beam 5A (double line) generated from the laser oscillator 5 can pass through the transparent optical window 12 that is hermetically attached to the wall of the vacuum container 7 to irradiate the flat plate electrode 6. The inside of the vacuum container 7 is always kept in vacuum, and a DC voltage can be applied between the flat plate electrode 6 and the counter electrode 10.

In FIG. 2, the conductive layer 1 (graphite) of the thin film display element to be manufactured is set inside the vacuum container 7 and the flat plate electrode 6 is irradiated with the laser beam 5A. As a result, ablation occurs on the surface of the flat plate electrode 6,
Carbon atom is released. The liberated carbon atoms travel in the range 5B indicated by the alternate long and short dash line and are deposited on the surface of the conductive layer 1 to form the insulating thin film 2. Next, the rare gas is caused to flow from the gas supply unit 9 into the gas passage 11 and blown out from the counter electrode 10. The rare gas flows in a cylindrical shape between the counter electrode 10 and the flat plate electrode 6. When a voltage is applied between the counter electrode 10 and the plate electrode 6 to cause a dielectric breakdown between the electrodes, a cylindrical plasma is formed. This plasma is moved to the central axis side of the cylinder by the magnetic field formed by itself, and the elongated pinch plasma 8 is formed. From the pinch plasma 8, carbon atoms liberated from the counter electrode 10 and the flat plate electrode 6 proceed in the range 8A indicated by the dotted line, and the conductive thin film 3 is formed on the surface of the insulating thin film 2. The thin film display device manufactured in this manner is
An insulating carbon thin film 2 having a diamond structure is formed on a carbon conductive layer 1 having a graphite structure, and a conductive carbon thin film 3 having a pseudo one-dimensional structure is further formed on the insulating thin film 2.

[0017]

As described above, according to the present invention, since the conductive layer, the insulating thin film and the conductive thin film of the thin film display element are all composed of a single atom of carbon atoms, the separation treatment at the time of disposal becomes unnecessary, Processing is easy. Further, in such a configuration, the conductive layer may be made of carbon having a graphite structure, the insulating thin film may be made of carbon having a diamond structure, and the conductive thin film may be made of carbon having a pseudo one-dimensional structure.
This prevents cracks in the insulating thin film, stabilizes the characteristics of the thin film display element, and prolongs its life.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a thin film display element according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an apparatus for manufacturing the thin film display element of FIG.

FIG. 3 is a perspective view showing a carbon bond of a graphite structure.

FIG. 4 is a perspective view showing a carbon bond of a diamond structure.

FIG. 5 is a diagram showing a carbon bond having a pseudo one-dimensional structure,
(A) is a side view of the main part, (B) is a plan view of the main part

FIG. 6 is a sectional view showing the structure of a conventional thin film display element.

[Explanation of symbols]

1: conductive layer, 2: insulating thin film, 3: conductive thin film, 4: carbon atom, 5A: laser light, 8: pinch plasma

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Claims (3)

(57) [Claims] 1. A thin film display device comprising an insulating thin film formed on the surface of a conductive layer and a conductive thin film formed on the surface of the insulating thin film on the side opposite to the conductive layer, wherein the conductive layer, the insulating thin film and the conductive thin film are all made of carbon. A thin film display element characterized by being composed of atoms. 2. The thin film display element according to claim 1,
A thin film display element characterized in that the conductive layer is made of carbon having a graphite structure, the insulating thin film is made of carbon having a diamond structure, and the conductive thin film is made of carbon having a pseudo one-dimensional structure. 3. A method of manufacturing a thin film display element according to claim 2, wherein carbon vapor generated from a graphite material by irradiation of laser light is deposited on a conductive layer to form an insulating thin film. A method for manufacturing a thin film display element, comprising forming a conductive thin film by irradiating a pinch plasma generated between a pair of graphite electrodes on the substrate.