KR20060001434A - Electron-emitting device - Google Patents

Abstract

The present invention relates to an electron emitting device for improving the arrangement structure of the electron emitting unit for emitting electrons to increase the amount of emission current,

A first substrate and a second substrate disposed to face each other; Cathode electrodes formed on the first substrate; Electron emission parts formed on the cathode electrodes, the electron emission parts being formed at random intervals from each other such that at least one pair corresponds to a direction crossing the cathode electrode; Provided is an electron emission device including gate electrodes formed over cathode electrodes and electron emission portions with an insulating layer interposed therebetween, and gate electrodes having openings for correspondingly exposing each electron emission portion.

Electron emission, electron emission unit, cathode electrode, gate electrode, insulating layer, anode electrode, fluorescent layer

Description

Electron Emission Device {ELECTRON EMISSION DEVICE}

1 is a partially exploded perspective view illustrating an electron emission device according to an exemplary embodiment of the present invention.

2 is a partial cross-sectional view showing the assembled state of FIG.

3 is a partial plan view of the electron emission unit illustrated in FIG. 1.

4 is a partial plan view of the electron emission unit shown to explain a modification of the electron emission unit.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron emitting device, and more particularly, to an electron emitting device for improving an amount of emission current by improving an arrangement structure of an electron emitting unit for emitting electrons.

In general, an electron emission device includes a method using a hot cathode and a cold cathode as an electron source. Among them, the electron-emitting devices using the cold cathode include Field Emitter Array (FEA), Metal-Insulator-Metal (MIM), Metal-Insulator-Semiconductor (MIS), Surface Conduction Emitter (SCE), and BSE (Ballistic electron Surface Emitter) type electron emission devices and the like are known.

Although the detailed structure of the electron emitting devices is different depending on the type, basically, an electron emission unit is provided on one of the substrates constituting the vacuum container to emit electrons therefrom, and the fluorescent layer is provided on the other substrate. It provides a predetermined light emission or display action.

Among the above-mentioned electron emission devices, the FEA type forms an electron emission portion made of materials which emit electrons when an electric field is applied, and includes driving electrodes, for example, a cathode electrode and a gate electrode, around the electron emission portion. When the electric field is formed around the electron emission portion by the inter-voltage difference, the principle that electrons are emitted therefrom is used.

One typical structure of the FEA type electron emission device is to sequentially form cathode electrodes, an insulating layer and a gate electrode on a first substrate, and each opening in the gate electrode and the insulating layer for each intersection region of the cathode and gate electrodes. Is formed to expose a part of the surface of the cathode electrode, and then the electron emission portion is formed on the cathode electrode into the opening.

In the above structure, as the gate electrode is formed surrounding the electron emitter on the electron emitter, an electric field formed by the voltage difference between the cathode electrode and the gate electrode tends to be concentrated at the edge of the electron emitter closest to the gate electrode. Therefore, the electron emitting portion emits the most electrons at the edge rather than the upper surface thereof, and it can be expected to increase the amount of emission current when increasing the edge length of the electron emitting portion. However, the conventional electron emitting device has a certain limit in increasing the amount of emission current because the consideration is not made enough when forming the electron emitting portion.

Accordingly, an object of the present invention is to provide an electron emission device capable of increasing the amount of emission current by maximizing the edge length of an electron emission portion in which an electric field is concentrated, and consequently increasing the screen brightness. have.

In order to achieve the above object, the present invention,

The first and second substrates disposed opposite to each other, the cathode electrodes formed on the first substrate, and the cathodes formed on the cathode electrodes and disposed at random intervals so that at least one pair correspond to each other in a direction crossing the cathode electrodes. The present invention provides an electron emission device including electron emission portions formed and gate electrodes formed on cathode electrodes and electron emission portions with an insulating layer interposed therebetween, and openings corresponding to each electron emission portion to expose the electron emission portions.

The electron emission parts may be arranged in plural along the direction of the cathode electrode for each pixel area set on the first substrate.

Each of the electron emission parts may be formed in a triangle, and the electron emission parts may be formed in pairs to face one side of the triangle. In particular, each of the electron emission portions may be formed as a right triangle, and the electron emission portions disposed while facing the hypotenuse of the right triangle may be formed in a pair.                     

The electron emission parts may be formed at random intervals so that a pair corresponds to the cathode electrode direction. In this case, each of the electron emission portions may be formed as a triangle, and the electron emission portions disposed while facing each vertex of the triangle may be formed in a pair.

The electron emission unit includes at least one of a carbonaceous material and a nanometer size material.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a partially exploded perspective view of an electron emission device according to an exemplary embodiment of the present invention, FIG. 2 is a partial cross-sectional view illustrating an assembled state of FIG. 1, and FIG. 3 is a partial plan view of the electron emission unit illustrated in FIG. 1.

Referring to the drawings, the electron-emitting device is a vacuum container that is the appearance of the electron-emitting device by arranging the first substrate 2 and the second substrate 4 in parallel at a predetermined interval so as to form an internal space, and bonding them together. Consists of. The first substrate 2 of the substrates 2 and 4 is provided with an electron emission unit 100 for emitting electrons, and the second substrate 4 is provided with a light emitting unit 200 for emitting visible light by electrons. Is provided.

More specifically, on the first substrate 2, the cathode electrodes 6 having a predetermined pattern, for example, a stripe shape, have one direction (y-axis direction in the drawing) of the first substrate 2 at random intervals from each other. Accordingly, the insulating layer 8 is formed on the entirety of the first substrate 2 while covering the cathode electrodes 6. On the insulating layer 8, a plurality of gate electrodes 10 are formed along the direction (x-axis direction in the drawing) crossing the cathode electrode 6 at random intervals from each other.

In the present exemplary embodiment, when the intersection region of the cathode electrode 6 and the gate electrode 10 is defined as a pixel region, a plurality of electron emission parts 12 are formed in each pixel region over the cathode electrode 6, and the gate electrode A plurality of openings 10a and 8a are formed in the 10 and the insulating layer 8 to expose the electron emission portions 12 and to expose them.

The electron emission unit 12 is formed of materials that emit electrons when an electric field is applied, such as a carbon-based material or a nanometer-sized material. Preferred carbon-based materials for use as the electron emitter 12 include carbon nanotubes, graphite, diamond-like carbon, C ₆₀ and combinations thereof. Nanometer-sized materials include nanotubes, nanowires, nanofibers, and the like. There is a combination material.

By the above-described structure, the gate electrode 10 is formed to surround each of the electron emission portions 12 on the electron emission portions 12, and a predetermined driving voltage is applied to the cathode electrode 6 and the gate electrode 10. When applied, the electric field is concentrated around the electron emitting portion 12, particularly at the edge portion of the electron emitting portion 12, due to the voltage difference between the two electrodes, thereby producing a large amount of electron emission.

Here, the electron emission device of the present embodiment arranges the electron emission portions 12 as follows in order to increase the edge length of the electron emission portions 12 where the electric field is concentrated.                     

In the present embodiment, the electron emitters 12 are separated into at least two electron emitters 12 at random intervals so that the pairs correspond to each other along the gate electrode direction (x-axis direction of the drawing), and the gate electrode The pair of electron emission portions 12 separated along the (10) direction are arranged in plural along the cathode electrode direction (y-axis direction in the drawing). In particular, each electron emitter 12 is formed in a triangle, and a pair of electron emitters 12 are disposed facing each other of the triangle. At this time, the planar shape of each of the electron emitting portions 12 is preferably a right triangle, the pair of electron emitting portions 12 may be arranged facing the hypotenuse of the right triangle.

As a result, the electron emission device of the present embodiment can extend the line length of the electron emission portion 12, that is, the length of the outline, without causing a large change in the area of the electron emission portions 12, and thus the electron emission portions 12 in which the electric field is concentrated. It can effectively extend the edge length of the.

Next, on one surface of the second substrate 4 facing the first substrate 2, a fluorescent layer 14, for example, red, green, and blue fluorescent layers 14 are formed at random intervals, The black layer 16 may be formed between the fluorescent layers 14 to improve contrast of the screen. An anode electrode 18 made of a metal film (for example, an aluminum film) by vapor deposition is formed on the fluorescent layer 14 and the black layer 16. The anode 18 receives a voltage necessary for accelerating the electron beam from the outside and increases the brightness of the screen by a metal back effect.

Meanwhile, the anode electrode may be made of a transparent conductive film, for example, an ITO film, rather than a metal film. In this case, an anode electrode (not shown) made of a transparent conductive film is first formed on the second substrate 4, and a fluorescent layer 14 and a black layer 16 are formed thereon, and a fluorescent layer 14 as necessary. ) And the black layer 16 can be used to increase the brightness of the screen. The anode electrode may be formed on the entire second substrate 4 or may be divided into a predetermined pattern.

For reference, in FIG. 2, reference numeral 20 denotes a spacer for maintaining a gap between the first substrate 2 and the second substrate 4. In FIG. 2, one spacer 20 is illustrated for convenience, but a plurality of spacers 20 are provided between the substrates 2 and 4.

In the electron emission device configured as described above, when a predetermined driving voltage is applied to the cathode electrode 6 and the gate electrode 10, an electric field is formed around the electron emission portion 12 due to the voltage difference between the two electrodes. Electrons are emitted, and the emitted electrons are attracted to the second substrate 4 by the high voltage applied to the anode electrode 18 and collide with the fluorescent layer 14 of the corresponding pixel to emit a predetermined light emission or display action. do.

At this time, the electron emission element of the present embodiment may increase the amount of electrons emitted from the electron emission portions 12 as the edge length of the electron emission portions 12 in which the electric field is concentrated increases, resulting in the brightness of the screen. It is anticipated that the advantages of increasing the power consumption and enabling the low voltage driving are possible.

Meanwhile, in the above, the case where the pair of electron emission parts 12 are disposed along the gate electrode direction (x-axis direction in the drawing) is described. However, as shown in FIG. 4, the electron emission parts 22 are directed toward the cathode electrode. It is also possible to have a structure in which a pair is arranged correspondingly along the (y-axis direction in the drawing) and the gate electrode direction (x-axis direction in the drawing).                     

Referring to FIG. 4, each electron emitter 22 consists of a triangle, preferably an isosceles triangle, and the pair of electron emitters 22 facing along the cathode electrode direction and the gate electrode direction is one of the triangles. Place vertices facing each other. Thus, in the above structure, four electron emitters 22 are formed in one group, and although not illustrated, the electron emitters 22 are arranged in plural along the cathode electrode direction (y-axis direction in the drawing). .

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to

As described above, the electron emission device according to the present invention can increase the amount of electrons emitted from the electron emission portion as the electron emission portions are formed to extend the edge length thereof. Therefore, the electron emission device according to the present invention has the effect of increasing the brightness of the screen and lowering the driving voltage.

Claims (8)

A first substrate and a second substrate disposed to face each other; Cathode electrodes formed on the first substrate; Electron emission parts formed on the cathode electrodes, the electron emission parts being formed at random intervals so that at least one pair corresponds to each other in a direction crossing the cathode electrodes; And Gate electrodes formed on the cathode electrodes and the electron emission parts with an insulating layer interposed therebetween and having openings for exposing the electron emission parts to correspond to the respective electron emission parts. Electron emitting device comprising a. The method of claim 1, And a plurality of electron emission parts arranged along the direction of the cathode electrode for each pixel area set on the first substrate. The method according to claim 1 or 2, Each of the electron emission parts is formed in a triangle, and the electron emission elements are paired with the electron emission parts arranged to face each other of the sides of the triangle. The method of claim 3, Each of the electron emission parts is formed as a right triangle, and the electron emission elements are paired with the electron emission parts arranged to face each other with the hypotenuse of the right triangle. The method according to claim 1 or 2, And an electron emission element formed at random intervals so that the pair corresponds to each other along the cathode electrode direction. The method of claim 5, Each of the electron emission parts is formed in a triangle, and the electron emission elements are paired with the electron emission parts arranged to face each other vertex of the triangle. The method of claim 1, And the electron emission unit comprises at least one of a carbon-based material and a nanometer-sized material. The method of claim 1, And an anode electrode formed on the second substrate and a fluorescent layer formed on one surface of the anode electrode.

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