KR20070046538A - Electron emission device and electron emission display device with the same - Google Patents

Abstract

The present invention relates to an electron emission device and an electron emission display device using the same that can enhance the focusing performance of the electron beam and effectively block the influence of the anode field on the electron emission portion. The formed cathode electrodes, the electron emission parts electrically connected to the cathode electrodes, the gate electrodes positioned on the cathode electrodes with the first insulating layer interposed therebetween, and the gate electrode with the second insulating layer interposed therebetween. It includes a focusing electrode formed on the upper portion. At this time, the first insulating layer, the gate electrodes, the second insulating layer and the focusing electrode form respective openings communicating with each other to open the electron emission portion, and the second insulating layer forms an opening having a width larger than that of the gate electrode. In addition, the focusing electrode forms an opening having a smaller width than that of the gate electrode.

Cathode electrode, gate electrode, electron emission part, insulating layer, direct growth, focusing electrode, anode electrode, fluorescent layer

Description

ELECTRON EMISSION DEVICE AND ELECTRON EMISSION DISPLAY DEVICE WITH THE SAME}

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

2 is a partial cross-sectional view of an electron emission display device according to an embodiment of the present invention.

3 is a partially enlarged view of FIG. 2.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron emission device, and more particularly, to an electron emission device having an improved shape of an opening of a focusing electrode in order to increase electron beam focusing performance, and an electron emission 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 emission device using the cold cathode may be a field emitter array (FEA) type, a surface conduction emission type (SCE) type, a metal insulating layer, a metal insulating layer, or a metal insulating layer. Metal (MIM) type and Metal-Insulator-Semiconductor (MIS) type are known.

Among them, the FEA type electron emission device includes 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 a work function is formed as a constituent material of the electron emission portion. Materials using low or high aspect ratios, such as carbon nanotubes (CNT) and carbon-based materials such as graphite and diamond-like carbon (DLC), utilize the principle of electron emission easily by an electric field in vacuum.

On the other hand, the electron-emitting device is arranged in an array on one substrate to form an electron emission device, the electron-emitting device is combined with another substrate having a light emitting unit consisting of a fluorescent layer, an anode electrode, etc. An emission display device is configured.

That is, the conventional electron emitting device includes a plurality of driving electrodes that function as scan electrodes and data electrodes in addition to the electron emitting part, thereby controlling the on / off and electron emission amount of electron emission for each pixel by the action of the electron emitting part and the driving electrodes. To control. 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 have a form in which driving electrodes are stacked with an insulating layer interposed therebetween. 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 then into the opening. The electron emission part is disposed on the cathode electrodes.

The electron emitting device may further comprise a focusing electrode for electron beam focusing. For example, in the case of the FEA type electron emission device described above, an additional insulating layer and a focusing electrode are formed on the gate electrodes, and respective openings communicating with the opening are also formed in the focusing electrode and the additional insulating layer to expose the electron emission portion.

At this time, the conventional electron emission device forms an opening of the focusing electrode to a width larger than that of the gate electrode for the convenience of the manufacturing process while facilitating the electron beam passage.

However, in the above-described structure, when the electrons emitted from the electron emission part pass through the opening of the focusing electrode, the focusing electrode is located far with respect to the electron beam path, so that the focusing efficiency is low. As a result, when the electrons reach the fluorescent layer, an electron beam spot larger than the fluorescent layer may be formed to cause display quality degradation such as light emission.

On the other hand, a high voltage (approximately hundreds to thousands of volts of voltage) required for electron beam acceleration is applied to the anode electrode provided in the light emitting unit. This causes unintended electron emission. At this time, the focusing electrode partially blocks the influence of the anode electric field on the electron emission portion, but as described above, the anode field shielding effect is low in the structure in which the opening has a large width in the focusing electrode.

Accordingly, an object of the present invention is to provide an electron emission device and an electron emission display device using the same, which can enhance electron beam focusing performance and effectively block the influence of an anode field on an electron emission unit. have.

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

A substrate, cathode electrodes formed on the substrate, electron emission portions electrically connected to the cathode electrodes, gate electrodes positioned on the cathode electrodes with the first insulating layer interposed therebetween, and the second insulating layer. A focusing electrode formed over the gate electrodes, the first insulating layer, the gate electrodes, the second insulating layer, and the focusing electrode forming respective openings communicating with each other to open the electron emission portion; 2 provides an electron emitting device in which the insulating layer forms an opening having a larger width than the opening of the gate electrode, while the focusing electrode forms an opening having a smaller width than the opening of the gate electrode.

The focusing electrode opening may have a width equal to or smaller than that of the electron emission part.

The catalyst layer may be positioned between the cathode electrode and the electron emission unit, and the electron emission unit may be formed of a carbon-based material grown on the catalyst layer.

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

First and second substrates disposed opposite to each other, cathode electrodes formed on the first substrate, electron emission portions electrically connected to the cathode electrodes, and the first insulating layer interposed therebetween Gate electrodes positioned on the substrate, a focusing electrode formed on the gate electrodes with the second insulating layer interposed therebetween, fluorescent layers formed on one surface of the second substrate, and an anode electrode formed on one surface of the fluorescent layers Wherein the first insulating layer, the gate electrodes, the second insulating layer and the focusing electrode form respective openings in communication with each other to open the electron emission portion, and the second insulating layer has a larger width than the opening of the gate electrode. Provided is an electron emission display device in which an opening is formed and the focusing electrode has an opening having a width smaller than that of the gate electrode.

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

1 and 2 are partially exploded perspective and partial cross-sectional views of an electron emission display device according to an exemplary embodiment of the present invention, respectively.

Referring to the drawings, the electron emission display device includes a first substrate 10 and a second substrate 12 which are disposed 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 12 to bond the two substrates, and the internal space is evacuated with a vacuum of approximately 10 ⁻⁶ torr to form the first substrate 10. ), The second substrate 12 and the sealing member constitute a vacuum container.

On the opposite surface of the first substrate 10 to the second substrate 12, electron emission elements are arranged in an array to form the electron emission device 100, and the electron emission device 100 is connected to the second substrate 12. ) And the light emitting unit 110 provided on the second substrate 12 to form an electron emission display device.

First, the cathode electrodes 14, which are first electrodes, are formed in a stripe pattern along one direction of the first substrate 10 on the first substrate 10, and cover the cathode electrodes 14. 10) The first insulating layer 16 is formed on the whole. Gate electrodes 18, which are second electrodes, are formed on the first insulating layer 16 in a stripe pattern along a direction orthogonal to the cathode electrodes 14.

In the present exemplary embodiment, when the intersection region of the cathode electrode 14 and the gate electrode 18 is defined as a pixel region, one or more electron emission portions 20 are formed in each pixel region over the cathode electrodes 14, and the first region is formed. Openings 161 and 181 corresponding to the electron emission portions 20 are formed in the insulating layer 16 and the gate electrode 18 to expose the electron emission portions 20 on the first substrate 10.

The electron emission unit 920 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-sized material. The electron emission unit 20 may include, for example, carbon nanotubes (CNT), graphite, graphite nanofibers, diamonds, diamond-like carbons (DLC), C ₆₀ , silicon nanowires, and combinations thereof. Screen printing, direct growth, chemical vapor deposition or sputtering can be applied.

2 and 3 schematically illustrate, for example, an electron emission unit 20 ′ fabricated by directly growing a carbon-based material. The electron emission portion 20 'by the direct growth method requires a catalyst layer 22 beneath it, and the catalyst layer 22 may be made of iron, nickel, cobalt or an alloy of three metals.

The direct growth method includes an electric discharge method, a laser deposition method, a plasma chemical vapor deposition method and a thermal chemical vapor deposition method. Among them, the plasma chemical vapor deposition method has an advantage of synthesizing carbon-based materials at 550 ° C. or less, which is the deformation temperature of soda-lime glass, which is mainly used as a substrate of electron emission devices, and the thermal chemical vapor deposition method is used to synthesize high purity materials There is an advantage in that it is suitable, the microstructure can be controlled, the device is simple and the mass synthesis is advantageous.

When the plasma chemical vapor deposition method and the thermal chemical vapor deposition method are applied, the catalyst layer is etched using ammonia gas, hydrogen gas, or the like before synthesis of the carbon-based material on the catalyst layer 22. To form fine catalytic metal particles. This is because carbon-based materials are synthesized on these fine catalytic metal particles.

The plasma chemical vapor deposition process is to generate a glow discharge within the chamber or reaction by direct current or high frequency power applied to the electrodes sikimyeo synthetic carbon-based materials from the fine metal particles in the catalyst layer, as the reaction gas C ₂ H _2, CH ₄ , C ₂ H ₄ , C ₂ H ₆ , or CO gas is used. In the thermal chemical vapor deposition method, the carbon-based material is removed from the fine metal particles of the catalyst layer 22 by installing the first substrate 10 in a quartz reaction tube in which a heating coil is installed, and flowing a reaction gas into the quartz reaction tube. Synthesize

In FIG. 1, two electron emitters 20 are arranged in a line along the length direction of the cathode electrode 14 in each pixel area. However, the number and arrangement of electron emitters 20 per pixel area may be described. The present invention is not limited to the illustrated example and can be variously modified.

A focusing electrode 24, which is a third electrode, is formed on the gate electrodes 18 and the first insulating layer 16. A second insulating layer 26 is positioned below the focusing electrode 24 to insulate the gate electrodes 18 and the focusing electrode 24, and passes the electron beam through the second insulating layer 26 and the focusing electrode 24. Openings 261 and 241 are provided. The openings 261 and 241 are provided for each electron emission unit 20 so that the focusing electrode 24 individually collects electrons emitted from each electron emission unit 20.

In this case, when the electron emission part is formed of a directly grown carbon-based material, an insulating material may be coated by chemical vapor deposition (CVD) to form the first insulating layer 16 and the second insulating layer 26.

In the present exemplary embodiment, the second insulating layer 26 forms an opening 261 having a width larger than that of the opening 181 of the gate electrode 18, while the focusing electrode 24 is an opening 181 of the gate electrode 18. An opening 241 having a width smaller than the width of the N-th width is formed to form an electron beam passing region smaller than the gate electrode 18.

That is, a part of the focusing electrode 24 protrudes and is not supported by the second insulating layer 26 on the electron emission part 20, and the protruding focusing electrode 24 is directly disposed with the vacuum interposed therebetween. It faces the electron emission part 20. In particular, the opening 241 of the focusing electrode 24 may be formed to have the same or smaller width than the electron emission part 20.

The second insulating layer 26 and the focusing electrode 24 may be formed by coating an insulating material on the first insulating layer 16 and the gate electrodes 18 to form a second insulating layer 26. A conductive material is coated on the insulating layer 26 to form the focusing electrode 24, and the focusing electrode 24 is patterned to form the opening 241, and the second insulating layer exposed by the opening 241 ( 26) When the part is wet etched to form the opening 261, the second insulating layer 26 is easily etched to generate an under-cut under the focusing electrode 24. Can be formed.

Next, on one surface of the second substrate 12 opposite to the first substrate 10, the fluorescent layer 28, for example, the red, green, and blue fluorescent layers 28R, 28G, and 28B may be randomly selected from each other. It is formed at intervals, and a black layer 30 is formed between the fluorescent layers 28 to improve the contrast of the screen.

An anode electrode 32 made of a metal film such as aluminum is formed on the fluorescent layer 28 and the black layer 30. The anode electrode 32 receives the high voltage necessary for accelerating the electron beam from the outside to maintain the fluorescent layer 28 in a high potential state, and visible light emitted toward the first substrate 10 of the visible light emitted from the fluorescent layer 28. Is reflected toward the second substrate 12 to increase the brightness of the screen.

On the other hand, the anode electrode may be made of a transparent conductive film such as ITO, in which case the anode electrode is located on one surface of the fluorescent layer 28 and the black layer 30 facing the second substrate 12. Moreover, the structure which uses simultaneously the above-mentioned transparent conductive film and a metal film as an anode electrode is also possible.

Spacers 34 (see FIG. 2) are disposed between the first substrate 10 and the second substrate 12 to support the compressive force applied to the vacuum container and to keep the distance between the two substrates constant. The spacers 34 are positioned corresponding to the black layer 30 so as not to invade the fluorescent layer 28.

The electron emission display device having the above-described configuration is driven by supplying a predetermined voltage to the cathode electrodes 14, the gate electrodes 18, the focusing electrode 24, and the anode electrode 32 from the outside.

For example, any one of the cathode electrodes 14 and the gate electrodes 18 receives a scan driving voltage to serve as scan electrodes, and the other electrodes receive a data driving voltage to serve as data electrodes. In addition, the focusing electrode 24 receives a voltage required for electron beam focusing, for example, 0 V or a negative DC voltage of several to several tens of volts, and the anode electrode 32 requires a voltage for accelerating the electron beam, for example, several hundred to several thousand volts. DC voltage of is applied.

As a result, an electric field is formed around the electron emission part 20 in the pixels in which the voltage difference between the cathode electrode 14 and the gate electrode 18 is greater than or equal to the threshold, and electrons are emitted therefrom. The emitted electrons are focused to the center of the electron beam bundle while passing through the opening 241 of the focusing electrode 24, and attracted by the high voltage applied to the anode electrode 32 to collide with the corresponding fluorescent layer 28 to emit light.

Referring to FIG. 3, as the focusing electrode 24 forms an opening 241 having a width smaller than that of the opening 181 of the gate electrode 18 in the above-described driving process, the predetermined distance from the electron emission part 20 may be reduced. Electrons emitted and diffused with the divergence angle do not pass through the opening 241 of the focusing electrode 24 and are blocked by the focusing electrode 24. As a result, the electrons passing through the focusing electrode 24 have excellent directivity toward the second substrate 12 and can suppress the emission of other colors due to the electron beam spreading.

In addition, the focusing electrode 24 reduces the exposure area of the electron emission part 20 toward the second substrate 12 due to the opening 241 described above, thereby effectively reducing the influence of the anode electric field on the electron emission part 20. Let's do it. Therefore, the malfunction of the anode electric field can be prevented, and a high voltage can be applied to the anode electrode 32 to increase the brightness of the screen.

As the second insulating layer 26 forms an opening 261 having a width larger than that of the opening 181 of the gate electrode 18, electron collision with the sidewall of the opening 261 of the second insulating layer 26 may occur. This reduces charge charging, resulting in more stable driving characteristics.

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 display device according to the present invention forms an opening having a smaller width than that of the gate electrode in the focusing electrode, thereby increasing the straightness of the electrons and suppressing the emission of the other colors. In addition, since the focusing electrode effectively blocks the influence of the anode electric field on the electron emitter, a high voltage can be applied to the anode, thereby realizing a high brightness screen.

Claims (6)

A substrate; Cathode electrodes formed on the substrate; Electron emission parts electrically connected to the cathode electrodes; Gate electrodes positioned on the cathode electrodes with a first insulating layer interposed therebetween; And A focusing electrode formed on the gate electrodes with a second insulating layer interposed therebetween. Including; The first insulating layer, the gate electrodes, the second insulating layer and the focusing electrode form respective openings in communication with each other to open the electron emission portion, And the second insulating layer forms an opening having a larger width than the opening of the gate electrode, and wherein the focusing electrode forms an opening having a smaller width than the opening of the gate electrode. The method of claim 1, And the focusing electrode opening is formed to have a width equal to or smaller than the electron emission portion. The method of claim 1, And the electron emitting portion 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, Further comprising a catalyst layer located between the cathode electrode and the electron emitting portion, And the electron emitting portion is made of a carbon-based material grown on the catalyst layer. The method of claim 4, wherein And the catalyst layer is made of any one material selected from the group consisting of iron, nickel, cobalt and alloys thereof. An electron emitting device according to any one of claims 1 to 5; Another substrate disposed to face the substrate; Fluorescent layers formed on one surface of the other substrate; And And an anode electrode formed on one surface of the fluorescent layers.

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