KR20070047460A - Electron emission device and electron emission display device using the same - Google Patents

Abstract

The present invention relates to an electron emission device capable of effectively focusing an electron beam emitted by improving the structure of a focusing electrode, and an electron emission display device using the same, wherein the electron emission device according to the present invention is formed on a substrate and the substrate. A focusing electrode formed on the substrate, the driving electrodes provided on the substrate to control the emission of electrons from the electron emitting sections, and insulated from the driving electrodes on the driving electrodes, and forming openings for passing an electron beam; An electrode. In this case, the focusing electrode may be configured of a plurality of layers to focus the electron beam more effectively.

Focusing electrode, amorphous silicon, gate electrode, cathode electrode

Description

ELECTRON EMISSION DEVICE AND ELECTRON EMISSION DISPLAY DEVICE USING THE SAME

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

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

Fig. 3 is a state diagram showing the state of charge of electrons and ions at the time of forming a potential in the focusing electrode.

4 is a state diagram showing a state in which an electron beam is focused by a focusing electrode.

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 capable of effectively focusing an emitted electron beam and an electron emitting display device using the same.

In general, electron emission elements may be classified into a method using a hot cathode and a cold cathode according to the type of electron source.

Here, the electron-emitting device using the cold cathode may be a field array array (FEA) type, a surface conduction emission (SCE) type, a metal-insulation layer-metal : MIM) type and metal-insulation-semiconductor (MIS) type | mold are known.

 Among them, the FEA type electron emission device has an electron emission portion and a driving electrode for controlling electron emission of the electron emission portion, and includes one cathode electrode and one gate electrode, and the material of the electron emission portion has a low work function. For example, a material having a high aspect ratio, such as carbon nanotubes and carbon-based materials such as graphite and diamond-like carbon, uses a principle that electrons are easily released by an electric field in vacuum.

On the other hand, the electron emission elements are formed in an array on one substrate to form an electron emission device, and the electron emission device is combined with another substrate provided with a light emitting unit including a fluorescent layer, an anode electrode, and the like. An emission display device is configured.

That is, a conventional electron emitting device has a plurality of driving electrodes which function as scan electrodes and data electrodes in addition to the electron emitting part, so that the electron emitting part on / off and the electron for each pixel are operated by the action of the electron emitting part and the driving electrodes. Control the amount of release. In addition, the electron emission display device excites the fluorescent layer with electrons emitted from the electron emission unit to perform a predetermined light emission or display function.

The electron emission device may be formed by stacking driving electrodes, an insulating layer, and an electron emission unit. For example, in the known FEA type electron emission device, cathode electrodes, an insulating layer, and gate electrodes are sequentially formed on a substrate, and openings are formed in the gate electrodes and the insulating layer to expose a portion of the surface of the cathode electrode, and inside the opening. Thus, the electron emission parts are disposed on the cathode electrodes.

In addition, when a focusing electrode is further provided for electron beam focusing in a known FEA type electron emission device, cathode electrodes, a first insulating layer, a gate electrode, a second insulating layer and a focusing electrode are sequentially formed on a substrate, Openings are formed in the remaining layers except for the cathode electrodes to expose a portion of the surface of the cathode, and an electron emission portion is formed on the cathode inside the opening.

The electron emission display device is formed by coupling an electron emission device with the substrate provided with the light emitting unit via a spacer.

The FEA type electron emission device and the electron emission display device having such a structure have a focusing electrode on the second insulating layer, but it is difficult to constantly focus the electron beam emitted from the electron emission portion, and some electrons are formed in the light emitting unit. Since it does not excite the fluorescent layer that is present, it is charged by the collision with the spacer (charging) has a disadvantage of lowering the luminous efficiency of the fluorescent layer.

Accordingly, an object of the present invention is to provide an electron emission device and an electron emission display device using the same that can effectively focus the emitted electron beam by improving the structure of the focusing electrode.

In order to achieve the above object, an electron emission device according to an embodiment of the present invention includes a substrate, an electron emission portion formed on the substrate, and a drive provided on the substrate to control electron emission from the electron emission portions. And a focusing electrode disposed on the driving electrodes and insulated from the driving electrodes and forming openings for passing the electron beam, and the focusing electrode may be formed of a plurality of layers.

The focusing electrode may include a first focusing part positioned on an insulating layer provided on the driving electrode, and a second focusing part provided on the first focusing part.

The first focusing part is electrically connected to form a common electric potential, and the second connecting part is arranged with a positive ion at a portion contacting the first connecting part by a negative voltage of the first focusing part, and the first connecting part Negative electrons can be arranged in the part farther from the.

The first focusing part may be made of any one conductive metal selected from chromium (Cr), molybdenum (Mo), aluminum (Al), platinum (Pt), gold (Au), and silver (Ag).

The second focusing part may be formed of amorphous silicon.

The driving electrodes may include cathode electrodes and gate electrodes formed on different layers with an insulating layer interposed therebetween, and the electron emission portions may be formed at each crossing region of the cathode electrode and the gate electrode. It may be formed on the cathode electrode.

The focusing electrode may constitute an opening that simultaneously exposes the electron emission units at each crossing area.

In addition, an electron emission display device according to another exemplary embodiment of the present invention may include a first substrate and a second substrate disposed to face each other through a spacer, electron emission portions formed on the first substrate, and on the first substrate. Drive electrodes provided to control electron emission from the electron emission parts, a focusing electrode positioned to be insulated from the drive electrodes on the drive electrodes, and to form openings for passing an electron beam, on one surface of the second substrate Red, green, and blue fluorescent layers to be formed, the anode electrode formed on any one surface of the fluorescent layers, the focusing electrode may be composed of a plurality of layers.

The focusing electrode may form one opening for each unit pixel set in the substrate, and the fluorescent layers may correspond to one color for each unit pixel.

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

1 is an exploded perspective view illustrating a part of an electron emission display device according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

Referring to the drawings, the electron emission display device includes a first substrate 10 and a second substrate 30 which are arranged in parallel to each other at predetermined intervals. Sealing members (not shown) are disposed at the edges of the first substrate 10 and the second substrate 30 to bond the two substrates, and the internal space is evacuated with a vacuum of approximately 10 ⁻⁶ torr so that the first substrate 10 ), The second substrate 30 and the sealing member constitute a vacuum container.

On the opposite surface of the first substrate 10 facing the second substrate 30, electron emission elements are arranged in an array to form the electron emission device 100 together with the first substrate 10. The emission device 100 is coupled to the second substrate 30 and the light emitting unit 110 provided on the second substrate 30 via the spacer 38 to form an electron emission display device.

First electrodes 12 (hereinafter referred to as “cathode electrodes”) are formed on the first substrate 10 in a stripe pattern along one direction of the first substrate 10, and cover the cathode electrodes 12. The first insulating layer 14 is formed on the entire first substrate 10. On the first insulating layer 14, second electrodes 16 (hereinafter referred to as “gate electrodes”) are formed in a stripe pattern along a direction orthogonal to the cathode electrode 12.

When the intersection area between the cathode electrodes 12 and the gate electrodes 16 is defined as a unit pixel, electron emission parts 20 are formed for each unit pixel over the cathode electrodes 12. In addition, openings 141 and 161 corresponding to the electron emission parts 20 are formed in the first insulating layer 14 and the gate electrodes 16, and the electron emission parts 20 are formed on the first substrate 10. To be exposed.

The electron emission unit 20 may be formed of materials that emit electrons when an electric field is applied in a vacuum, such as a carbon-based material or a nanometer (nm) size material. The electron emission unit 20 may include carbon nanotubes (CNT), graphite, graphite nanofibers, diamonds, diamond phase carbons (DLC), C ₆₀ , silicon nanowires, and combinations thereof. Screen printing, direct growth, sputtering or chemical vapor deposition (CVD) can be applied.

On the other hand, the electron emission unit 20 may be formed of a tip structure having a sharp tip, such as molybdenum (Mo) or silicon (Si).

The electron emission units 20 may be disposed in a line along the length direction of one of the cathode electrode 12 and the gate electrode 16, for example, the cathode electrode 12, in each unit pixel, and may be disposed in a circular plane. It may be formed to have a shape. The arrangement of the electron emission units 20 and the planar shape of the electron emission units 20 for each pixel are not limited to the illustrated example, and may be variously modified.

In addition, in the above, the structure in which the gate electrodes 16 are positioned on the cathode electrodes 12 with the first insulating layer 14 therebetween has been described, but the gate electrodes have the first insulating layer interposed therebetween. A structure positioned below the electrodes is also possible, in which case the electron emission parts may be formed on the side of the cathode electrode over the first insulating layer.

A third electrode 24 (hereinafter, referred to as a "focus electrode") is formed on the gate electrodes 16 and the first insulating layer 14. The focusing electrode 24 is formed in a two-layer structure having a plurality of layer structures, for example, a first focusing part 241 and a second focusing part 242. A second insulating layer 22 is positioned below the focusing electrode 24 to insulate the gate electrodes 16 and the focusing electrode 24. In addition, openings 243, 244, and 221 for passing the electron beam are also provided in the first focusing part 241, the second focusing part 242, and the second insulating layer 22 of the focusing electrode 24.

The openings 243 and 244 of the focusing electrode 24 are formed for each unit pixel so that the first focusing part 241 and the second focusing part 242 of the focusing electrode 24 are emitted from one unit pixel. These may be collectively focused, or one may be formed for each opening 163 of each gate electrode 16 to individually focus electrons emitted from each electron emission unit 20. In the drawings, the former case is illustrated as an example.

In the present exemplary embodiment, the focusing electrode 24 includes the first focusing part 241 and the second focusing part 242 as described above to focus the electron beam path twice to further increase the focusing effect of the electron beam.

More specifically, the first focusing part 241 and the second focusing part 242 of the focusing electrode 24 may be disposed to correspond to the unit pixels to form the above-described openings 243 and 244 therein, and the second insulation may be formed. Formed on layer 22.

Here, the first focusing part 241 is preferably made of a conductive metal such as chromium (Cr), molybdenum (Mo), aluminum (Al), platinum (Pt), gold (Au), and silver (Ag).

Referring to FIG. 3, the first focusing parts 241 primarily focus electrons e ⁻ emitted from the electron emission part 20, and are electrically connected to each other and applied with a common focusing voltage. The second focusing parts 242 are formed in contact on the first focusing part 241 to form an array of ions and electrons by a negative focusing voltage applied to the first focusing part 241. That is, a negative voltage is applied to the first connection portion 241 so that negative electrons are arranged. Then, positive ions are arranged in a portion of the second connector 242 contacting the first connector 241, and negative electrons are arranged in a portion away from the first connector 241.

As a result, the electron beam emitted from the electron emitter 20 is first focused by the negative electrons of the first connector 241 (B1), and then secondly focused by the negative electrons of the second connector 242 ( B2) More effective focusing is possible.

That is, the second focusing part 242 secondly focuses some of the beams B1, which may be spread in a virtual line state, among the primary focusing beams B1 focused by the first connection part 241. Is prevented from being charged and impinged on the fluorescent layer 32 (see Fig. 4).

As such, the second focusing part 242 may be made of a semiconductor material, and may be formed of amorphous silicon, for example, so that charging may be caused by the focusing voltage applied to the first focusing part 241. . This amorphous silicon has strong mechanical strength, chemical stability and heat resistance. In order to maximize the focusing efficiency, such amorphous silicon may use intrinsic amorphous silicon that is not doped with impurities, or may use impurity amorphous silicon that is doped with an electron or a hole source.

In addition, the focusing electrode 24 may be formed of two or more focusing parts for effectively focusing the electron beam.

Meanwhile, on one surface of the second substrate 30 facing the first substrate 10, the fluorescent layer 32, for example, the red, green, and blue fluorescent layers 32R, 32G, and 32B are spaced apart from each other. The black layer 34 is formed between the fluorescent layers 32 to improve contrast of the screen. The fluorescent layer 32 is disposed so that one fluorescent layer 32 corresponds to each unit pixel set on the first substrate 10.

An anode electrode 36 made of a metal film such as aluminum (Al) is formed on the fluorescent layer 32 and the black layer 34. The anode 36 receives the high voltage necessary for accelerating the electron beam from the outside to maintain the fluorescent layer 32 in a high potential state, and the visible light emitted toward the first substrate 10 of the visible light emitted from the fluorescent layer 32. Is reflected toward the second substrate 30 to increase the brightness of the screen.

On the other hand, the anode electrode may be made of a transparent conductive film such as indium tin oxide (ITO) rather than a metal film. In this case, the anode is positioned on one surface of the fluorescent layer 32 and the black layer 34 facing the second substrate 30. Further, it is possible to have a structure in which the above-mentioned transparent conductive film and the metal film are simultaneously used as the anode electrode.

In addition, a plurality of spacers 38 are disposed between the first substrate 10 and the second substrate 30 to support the compressive force applied to the vacuum container and to keep the distance between the two substrates constant. These spacers 38 are positioned corresponding to the black layer 34 so as not to invade the fluorescent layer 32.

The above-described electron emission display device has a predetermined voltage from the outside to the cathode electrodes 12, the gate electrodes 16, the first focusing part 241, the second focusing part 242, and the anode electrode 36. It is driven by applying.

For example, any one of the cathode electrodes 12 and the gate electrodes 16 receives a scan driving voltage to serve as scan electrodes, and the other electrodes receive a data driving voltage to serve as data electrodes. .

The first focusing unit 241 receives a voltage required for focusing the electron beam, for example, 0 V or a negative DC voltage of several to several tens of volts, and the anode electrode 36 is a voltage for accelerating the electron beam, for example, hundreds to thousands A positive DC voltage of volts is applied.

Then, an electric field is formed around the electron emission portion 20 of the unit pixels whose potential difference between the cathode electrode 12 and the gate electrode 16 is greater than or equal to the threshold value, thereby emitting electrons therefrom. The emitted electrons are primarily focused to the center of the electron beam bundle while passing through the opening 243 of the first focusing portion 241, and 2 to the center of the electron beam bundle while passing through the opening 244 of the second focusing portion 242. The light is concentrated and attracted by the high voltage applied to the anode electrode 36 to collide with the fluorescent layer 32 of the corresponding unit pixel, thereby effectively emitting light.

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 the scope of the invention.

As described above, the electron emission device according to the present invention forms a plurality of focusing electrodes, and applies negative voltages of 0 volts or several to several tens of volts to the first focusing portion of the focusing electrode to form negative electrons. The electron beam is focused first, and positive ions are arranged at the contact portion of the first focusing part of the second focusing part with the application of the negative voltage, and negative electrons are arranged at the far part, whereby the first focused electron beam is focused. Since secondary electrons are focused by the negative electrons, the electron beam can be effectively focused, thereby preventing the electrons from colliding with the spacer and being charged. Therefore, the electron emitting device according to the present invention can improve the luminous efficiency of the fluorescent layer by focusing the emitted electron beam more effectively and colliding with the fluorescent layer.

Claims (9)

A substrate; Electron emission parts formed on the substrate; Drive electrodes provided on the substrate to control electron emission from the electron emission portions; And A focusing electrode which is insulated from the driving electrodes on the driving electrodes and forms openings for passing an electron beam, And said focusing electrode is composed of a plurality of layers. The method of claim 1, The focusing electrode may include a first focusing part positioned in an insulating layer provided on the driving electrode; And a second focusing portion provided on the first focusing portion. The method of claim 2, The first focusing portion is electrically connected to form a common potential, And the second connecting portion is arranged such that positive ions are arranged in a portion in contact with the first connecting portion and negative electrons are arranged in a portion away from the first connecting portion by a negative voltage of the first focusing portion. The method of claim 3, And the first focusing portion is made of any one conductive metal selected from chromium (Cr), molybdenum (Mo), aluminum (Al), platinum (Pt), gold (Au), and silver (Ag). The method of claim 2, And the second focusing portion is formed of amorphous silicon. The method of claim 2, The driving electrodes include cathode electrodes and gate electrodes which are formed in different layers with an insulating layer interposed therebetween and formed in an intersecting direction. And the electron emission portions are formed on the cathode electrode at every crossing region of the cathode electrode and the gate electrode. The method of claim 6, And the focusing electrode constitutes one opening that simultaneously exposes the electron emission portions at each of the crossing regions. An electron emitting device according to any one of claims 1 to 7; Another substrate disposed to face the substrate via a spacer; Red, green, and blue fluorescent layers formed on one surface of the other substrate; And And an anode electrode formed on one surface of the fluorescent layers. The method of claim 8, The focusing electrode forms one opening for each unit pixel set in the substrate, And the fluorescent layers correspond to one color per unit pixel.

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