KR20060019855A - Electron emission device - Google Patents

Abstract

The present invention relates to an electron emitting device capable of suppressing electron beam path distortion caused by spacer charging and focusing electrons to increase the color gamut of a screen.

A first substrate and a second substrate; Gate electrodes formed on the first substrate; An insulating layer formed on the first substrate while covering the gate electrodes; Cathode electrodes including line portions formed in one direction of the first substrate on the insulating layer and a plurality of extension portions extending from one end of each line portion in a direction crossing the line portion; Electron emission parts formed along a direction crossing the line part while in contact with the extension part; The present invention provides an electron emission device including spacers disposed between the first substrate and the second substrate and spaced apart from the electron emission portion along a direction crossing the line portion.

Spacer, electron charging, cathode electrode, gate electrode, electron emission part, anode electrode, fluorescent film, fusing electrode

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 of an electron emitting device according to an embodiment of the present invention.

3 is a partial plan view of an electron emission array among electron emission devices according to an exemplary embodiment of the present invention.

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 having an improved arrangement of an electron emitting unit, driving electrodes, and a spacer.

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 are field emitter array (FEA) type, surface conduction emitter (SCE) type, metal insulator metal (MIM) type, metal insulator semiconductor (MIS) type, and ballistic electron surface. Emitter type electron emission devices and the like are known.

Although the above-described electron emitting devices have different structures according to their types, basically, an electron emission array is formed on one of the two substrates constituting the vacuum container to emit electrons therefrom, and the fluorescent layer on the other substrate. In addition, the electron acceleration electrode is provided to allow the electrons to be well accelerated toward the fluorescent layer to perform a predetermined light emission or display function.

Among the above-mentioned electron emission devices, FEA type is a driving electrode that forms an electron emission portion with a material that emits electrons when an electric field is applied, and forms an electric field required for electron emission around the electron emission portion, for example, a cathode electrode and a gate electrode. It is provided to configure the electron emission array.

One known structure of an FEA type electron emission device includes a gate electrode, an insulating layer, and a cathode electrode sequentially formed on a first substrate, an electron emission portion formed at one edge of the cathode electrode, and a fluorescent layer on the second substrate. An anode electrode is formed. Thus, when a predetermined driving voltage is applied to the gate electrode and the cathode electrode, an electric field is formed around the electron emission part due to the potential difference between the two electrodes, and electrons are emitted therefrom, and the emitted electrons are attracted to the high voltage applied to the anode electrode. It collides with the fluorescent layer to emit light.

At this time, a plurality of spacers are disposed between the first substrate and the second substrate to maintain the two substrates at regular intervals, and to prevent the vacuum container from being deformed or damaged by the pressure difference between the inside and the outside of the vacuum container. .

However, as the recent electron emission devices become higher resolution, the driving electrodes and the electron emission parts are more densely disposed on the first substrate, which causes a large amount of electrons to travel around the spacer. Furthermore, in the above-described structure, when electrons are emitted from the electron emitting portion, electrons propagate obliquely at an arbitrary inclination angle from the first substrate, so that the electron beam path tends to spread widely.

Accordingly, charges are accumulated in the spacers while the electrons travel toward the second substrate, and the accumulated charges deteriorate the screen quality, such as distorting the electron beam path that travels around the electrons.

In addition, in the above-described structure, since no separate electrode or structure for the electron beam focusing is provided around the electron emission unit, the electrons do not have a constant straightness and are spread out. As a result, the electrons reach not only the fluorescent layer of the corresponding pixel but also the fluorescent layer of another adjacent pixel, thereby lowering the color reproduction of the screen.

Therefore, the present invention is to solve the above problems, an object of the present invention is to prevent the accumulation of charge in the spacer to prevent electron beam path distortion caused by the charge accumulation of the spacer, and to focus the electrons emitted from the electron emission portion screen To provide an electron emitting device that can increase the color gamut of the.

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

A first substrate and a second substrate opposed to each other with a vacuum region interposed therebetween, gate electrodes formed on the first substrate, an insulating layer formed on the first substrate while covering the gate electrodes, and a first substrate on the insulating layer. Cathodes including line portions formed along one direction of and a plurality of extension portions extending from one end of each line portion along a direction crossing the line portions, and a direction crossing the line portions while contacting the extension portion; According to an embodiment, there is provided an electron emission device including electron emission parts formed along the spacers and spaced apart from the electron emission parts along a direction intersecting the line part.

The line portions of the gate electrodes and the cathode electrode may be formed in a stripe pattern along a direction crossing each other, and the extension portions of the cathode electrode may be correspondingly disposed one by one between each gate electrode.

The electron emission device may further include an opposite electrode positioned on the insulating layer and spaced apart from the electron emission part and receiving the same voltage as the gate electrode.

The spacer may be positioned on the same line as the electron emission part along a direction crossing the line part of the cathode electrode, and disposed on the cathode electrodes.

The electron emission device further includes at least one anode electrode formed on the second substrate, and a fluorescent layer formed on one surface of the anode electrode. At this time, the fluorescent layer is disposed corresponding to each pixel region set on the first substrate, and the center of each pixel region set on the first substrate and the center of the fluorescent layer corresponding to the pixel region are in the direction of the line portion of the cathode electrode. Can be spaced apart along.

The cathode electrode receives a lower driving voltage than the gate electrode, preferably the cathode electrode receives a negative scan signal, and the gate electrode receives a positive data signal.

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 cross-sectional view of an electron emission device according to an exemplary embodiment of the present invention. 1 is a partial plan view of a substrate.

Referring to the drawings, the electron emission device includes a first substrate 1 and a second substrate 2 disposed to face each other with an internal space of a vacuum interposed therebetween. The first substrate 1 is provided with an electron emission array 10 for emitting electrons, and the second substrate 2 is provided with a light emitting portion 20 that emits visible light by electrons and emits any light or displays. do.

First, on the first substrate 1, gate electrodes 11 having a predetermined pattern, for example, a stripe shape, are arranged along one direction (y-axis direction in the drawing) of the first substrate 1 at random intervals from each other. A plurality of insulating layers 12 may be formed on the first substrate 1 while covering the gate electrodes 11. On the insulating layer 12, a plurality of cathode electrodes 13 are formed along the direction (x-axis direction in the drawing) crossing the gate electrode 11 at arbitrary intervals from each other.

The cathode electrode 13 has a stripe-shaped line portion 13a crossing the gate electrode 11 and a plurality of extensions extending from one end of the line portion 13a along the direction crossing the line portion 13a. Made of parts 13b. In the present exemplary embodiment, when the intersection of the line portion 13a of the cathode electrode 13 and the gate electrode 11 is defined as a pixel region, one extension portion 13b of the cathode electrode 13 is provided for each pixel. The position is preferably between the gate electrodes 11.

In this case, the extension parts 13b may have a width A measured in the direction of the gate electrode 11 (see FIG. 2) greater than a width B measured in the direction of the line portion 13a (see FIG. 2). Each extension 13b has a pair of long sides parallel to the gate electrode 11. In such a structure, the extension parts 13b can be densely arranged along the direction of the line part 13a (usually the horizontal direction of the screen) of the cathode electrode 13, which is advantageous for increasing the horizontal resolution of the screen.

In addition, an electron emission part 14 is formed in the extension part 13b of the cathode electrode 13 at least partially in contact with the extension part 13b so as to be electrically connected thereto. In particular, the electron emission portion 14 is formed in contact with and along the edge of one of the two long sides of the extension portion 13b, so that the electron emission portion 14 moves along the direction of the line portion 13a of the cathode electrode 13 when the electron emission element is driven. Make up the configuration.

In the present embodiment, the electron emission unit 14 is formed of materials emitting electrons when an electric field is applied, such as a carbon-based material or a nanometer (nm) size material. Preferred materials for use as the electron emitter 14 include any one of carbon nanotubes, graphite, graphite nanofibers, diamond, diamond-like carbon, C ₆₀ , silicon nanowires, or a combination thereof. As a method of manufacturing the electron emission unit 14, direct growth, screen printing, chemical vapor deposition, or sputtering may be applied.

In addition, an opposite electrode 15 may be formed on the insulating layer 12 and positioned on the same layer as the cathode electrode 13 and electrically connected to the gate electrode 11. The counter electrode 15 is positioned at an arbitrary distance from the electron emission portion 14 between each of the extension portions, and is connected to the gate electrode 11 through a via hole 12a formed in the insulating layer 12. In contact with and electrically connected to it.

When the counter electrode 15 drives an electron emission element, when a predetermined driving voltage is applied to the gate electrode 11 to form an electric field for electron emission around the electron emission unit 14, the counter electrode 15 is itself an electron emission unit ( Further field is formed for electron emission. As a result, the counter electrode 15 serves to allow electrons to be well emitted from the electron emission unit 14 while applying a low driving voltage to the gate electrodes 11.

In the present embodiment, the counter electrode 15 has a substantially rectangular shape, but the shape of the counter electrode 15 is not limited to the above-described example and can be variously modified.

Next, on one surface of the second substrate 2 facing the first substrate 1, a fluorescent layer 21, for example, red, green, and blue fluorescent layers are formed at random intervals, and the fluorescent layer ( The black layer 22 may be formed between the surfaces 21 to improve the contrast of the screen. On the fluorescent layer 21 and the black layer 22, an anode electrode 23 made of a metal film (for example, an aluminum film) by vapor deposition is formed.

The anode 23 receives a voltage (approximately, a positive voltage of several hundred to several thousand volts) required for electron beam acceleration from the outside, and increases the brightness of the screen by a metal back effect.                     

On the other hand, the anode electrode may be made of a transparent conductive film, for example, an indium tin oxide (ITO) film, not a metal film. In this case, an anode electrode (not shown) made of a transparent conductive film is first formed on the second substrate 2, and a fluorescent layer 21 and a black layer 22 are formed thereon, and a fluorescent layer 21 as necessary. ) And the black layer 22 can be used to increase the brightness of the screen. The anode electrode may be formed on the entire second substrate 2 or may be formed in plural in a predetermined pattern.

The first substrate 1 and the second substrate 2 having the above-described configuration are frits applied around the substrate at arbitrary intervals while the electron emission array 10 and the light emitting portion 20 face each other. It is bonded by a sealing material such as, and the electron emitting device is constituted by evacuating and maintaining a vacuum state of the internal spaces formed therebetween while placing a plurality of spacers 3 in the non-light emitting region between the two substrates.

In this case, the spacer 3 is spaced apart from the electron emitter 14 along the direction of the gate electrode 11, and more preferably, is positioned on the same line as the electron emitter 14 along the direction of the gate electrode 11. So that the spacer 3 is located as far as possible from the electron beam path.

In the electron emission device configured as described above, when a predetermined driving voltage is applied to the cathode electrode 13 and the gate electrode 11, an electric field is formed around the electron emission portion 14 due to the potential difference between the two electrodes. Electrons are emitted from the electrons, and the emitted electrons are attracted to the second substrate 2 by the high voltage applied to the anode electrode 23 and collide with the fluorescent layer 21 of the corresponding pixel to emit light.                     

In the driving process described above, electrons are emitted from the electron emission portion 14 along the direction of the line portion 13a of the cathode electrode 13 (see FIGS. 2 and 3), and the spacers 3 are connected to the gate electrode 11. The spacer 3 is located far from the electron beam path because it is spaced apart from the electron emitter 14 along the direction of (). Therefore, the electron emission device of the present embodiment can suppress the accumulation of charge in the spacer 3, thereby minimizing electron beam path distortion caused by the accumulation of charge in the spacer 3.

Nevertheless, considering the possibility that the spacer 3 is charged due to electrons hitting the spacer 3, the charge accumulated in the spacer 3 is formed by forming the spacer 3 on the cathode electrode 13. It is desirable to be drawn out through the.

In addition, when the driving voltage applied to the cathode electrode 13 is lower than the driving voltage applied to the gate electrode 11, the footing for focusing the electron beam on the neighboring pixel region is extended by the extension part 13b located in the specific pixel. Can function as a pushing electrode.

For example, a negative scan signal of several to several tens of volts may be applied to the cathode electrode 13, and a positive data signal of several to several tens of volts may be applied to the gate electrode 11. Accordingly, when the scan signal is sequentially applied to the cathode electrodes 13 and the data signal is selectively applied to the gate electrodes 11 corresponding to the selected cathode electrode 13, the electrons in the pixel in which the potential difference between the two electrodes is greater than or equal to the threshold value are applied. Release occurs.

If the pixel in which electron emission occurs is assumed as the third pixel from the left among the four pixels shown in FIG. 2, the extension part 13b positioned at the second pixel from the left is applied to the scan signal regardless of the on / off of the corresponding pixel. The negative potential is maintained. The extension 13b pushes the electrons emitted from the third pixel to increase the straightness of the electron beam, thereby improving the color reproduction of the screen.

On the other hand, in spite of the pushing function of the extension part 13b, the electrodes forming the electric field required for electron emission, that is, the gate electrode 11 and the counter electrode 15 are not located above the cathode electrode 13. Electrons emitted from the electron emission portion 14 travel obliquely at an angle of inclination from the first substrate 1.

In consideration of the electron beam trajectory, the center of the fluorescent layer 21 disposed corresponding to the pixel region with respect to the center of each pixel region set on the first substrate 1 is the line portion 13a of the cathode electrode 13. It is preferable to space along the direction, thereby allowing all of the electrons emitted from the electron emission unit 14 to reach the fluorescent layer 21 of the corresponding pixel. In FIG. 2, D denotes a separation distance between the center of the fluorescent layer 21 and the center of the pixel area.

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 That is, while the FEA type electron emission device has been described above, the present invention is not limited to the FEA type, and various modifications are possible.

As described above, the electron emission device according to the present invention minimizes the accumulation of charge in the spacer, thereby suppressing the electron beam distortion caused by the spacer charging and thus the misdischarge, thereby improving the screen quality. In addition, the electron emission device according to the present invention has an effect of improving the color gamut of the screen by increasing the straightness of the electron beam since the extension of the neighboring pixel functions as a pushing electrode.

Claims (12)

A first substrate and a second substrate facing each other with the vacuum region interposed therebetween; Gate electrodes formed on the first substrate; An insulating layer formed on the first substrate while covering the gate electrodes; Cathode electrodes including line parts formed along one direction of the first substrate on the insulating layer and a plurality of extension parts extending from one end of each line part in a direction crossing the line part; Electron emission parts formed along a direction crossing the line part while in contact with the extension part; And Spacers disposed between the first substrate and the second substrate and spaced apart from the electron emission part in a direction crossing the line part. Electron emitting device comprising a. The method of claim 1, And an stripe pattern formed along a direction in which line portions of the gate electrodes and the cathode electrode cross each other. The method of claim 2, And an extension part of the cathode electrode correspondingly disposed one by one between the respective gate electrodes. The method of claim 1, And a long side along the direction in which the extension parts of the cathode electrode and the electron emission parts intersect the line part. The method of claim 1, And an opposite electrode positioned on the insulating layer and spaced apart from the electron emission part and receiving the same voltage as the gate electrode. The method of claim 1, And the electron emission unit comprises at least one material selected from the group consisting of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, C ₆₀ and silicon nanowires. The method of claim 1, And an electron emission device disposed on the same line as the electron emission part along a direction in which the spacer intersects the line part of the cathode electrode. The method of claim 1, And the spacer is disposed over the cathode electrodes. The method of claim 1, And at least one anode electrode formed on the second substrate, and a fluorescent layer formed on one surface of the anode electrode. The method of claim 9, The fluorescent layer is disposed corresponding to each pixel region set on the first substrate, and the center of each pixel region set on the first substrate and the center of the fluorescent layer corresponding to the pixel region are directed toward the line portion of the cathode electrode. Electron emitting device is spaced apart along the. The method of claim 1, And the cathode is applied with a lower driving voltage than the gate electrode. The method of claim 11, And the cathode electrode receives a negative scan signal and the gate electrode receives a positive data signal.

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