KR20070106109A - Electron emission device and electron emission display device using the same - Google Patents

Abstract

An electron emission device and an electron emission display device using the same are provided to prevent variations of an electric field in an opening of a gate electrode by enlarging a short width of an isolated electrode than a long width of the opening. Cathode electrodes are formed on a substrate, and gate electrodes(18) are isolated from the cathode electrodes. A plurality of electron emission portions(20) are electrically connected to the cathode electrodes. The cathode electrode has a main electrode(141) forming an opening(141a) every unit pixel, an isolated electrode(142) spaced apart from the main electrode in the opening, and a resistant layer electrically connecting the main electrode with the isolated electrode. The gate electrode has an opening corresponding to the isolated electrode to expose the electron emission portions.

Description

ELECTRON EMISSION DEVICE AND ELECTRON EMISSION DISPLAY DEVICE USING THE SAME

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

FIG. 2 is a partial cross-sectional view of the electron emission display device shown in FIG. 1. FIG.

3 is a partial plan view illustrating a main electrode, an isolation electrode, and an electron emission unit of an electron emission device according to an exemplary embodiment of the present disclosure.

4 is a partial plan view illustrating a main electrode, an isolation electrode, and an electron emission unit of an electron emission device according to another exemplary embodiment of the present disclosure.

The present invention relates to an electron emission device and an electron emission display device using the same, and more particularly, to a cathode electrode electrically connected to an electron emission unit and supplying a current to the electron emission unit.

In general, an electron emission element 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 is a field emitter array (FEA) type, a surface conduction emission type (SCE) type, a metal-insulation layer-metal Metal (MIM) type and Metal-Insulator-Semiconductor (MIS) type are known.

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

The electron emission elements are arranged 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 composed of a fluorescent layer and an anode electrode, and the electron emission display device. (electron emission display device) is configured.

In the electron emission display device, an unstable driving voltage is applied to a cathode electrode which is electrically connected to the electron emission unit and supplies a current required for electron emission during driving, or a difference in voltage applied to the electron emission units due to the line resistance of the cathode electrode. May occur. In this case, the emission characteristics of the electron emission parts become nonuniform, leading to a decrease in the uniformity of emission for each pixel.

In order to solve the above problems, a structure for uniformizing the emission characteristics of the electron emission parts by supplying a current to the electron emission part through the resistance layer has been proposed and used. The cathode electrode structure includes a main electrode having an opening for each unit pixel, an isolation electrode formed inside the opening to place an electron emission unit, and a resistance layer electrically connecting the main electrode and the isolation electrode.

The gate electrode is insulated from the cathode electrode on the cathode, and an opening is formed in the gate electrode to expose a part of the surface of the main electrode.

By the way, the gate electrode opening formed in the upper part of the isolation electrode was designed in the same size as the isolation electrode conventionally. In this case, when the gate electrode opening is formed larger than the designed value due to manufacturing tolerances, or if a misalignment occurs between the main electrode and the gate electrode opening, the end of the main electrode is exposed by the gate electrode opening.

When the end of the main electrode is exposed by the gate electrode opening, a change in electric field occurs at this portion, which causes distortion of the electron beam trajectory, resulting in a decrease in color purity of the electron emission display device. In addition, the electric field change as described above has a problem of causing an emission unevenness and an increase in driving voltage.

Accordingly, an object of the present invention is to solve the above problems, and an object of the present invention is to prevent an end of a main electrode from being exposed to a gate electrode opening, thereby preventing an electric field change that may occur, and an electron emission display using the same. In providing a device.

In order to achieve the above object, an electron emission device according to an exemplary embodiment of the present invention includes a substrate, a cathode electrode formed on the substrate, a gate electrode positioned to be insulated from the cathode electrode, and an electron emission portion electrically connected to the cathode electrode. The cathode electrode includes a main electrode which forms an opening for each unit pixel set in the substrate, an isolation electrode in which the electron emission unit is disposed and spaced apart from the main electrode inside the opening, and electrically connects the main electrode and the isolation electrode. The gate electrode has an opening corresponding to the isolation electrode to expose the electron emission part on a substrate, and the short width of the isolation electrode is W _I , and the long width of the gate electrode opening is formed. When W _G is given, the following relation is satisfied.

W _I ＞ W _G

In addition, the short width of the isolation electrode and the long width of the gate electrode opening may satisfy the following conditions.

W _I / W _G = 1.0 ~ 1.5

In addition, an individual area of the isolation electrode may be larger than an individual area occupied by the gate electrode opening.

In addition, the gate electrode opening may be formed in a circular shape.

In addition, the isolation electrode may be formed in a rectangle or a hexagon.

In addition, the main electrode and the isolation electrode may be made of a transparent material.

In addition, the isolation electrodes may be positioned in a line along the length direction of the main electrode, and the resistance layer may be positioned at both sides of the isolation electrodes.

In addition, one main electrode opening may be formed in each unit pixel, and a plurality of isolation electrodes may be formed in the main electrode opening.

In addition, the electron emitting device according to the embodiment of the present invention can be applied to an electron emitting display device that emits light and displays. Accordingly, the electron emission display device according to the embodiment of the present invention, the electron emission device, the other substrate disposed to face the substrate, the fluorescent layer formed on one surface of the other substrate and the anode electrode formed on any one surface of the fluorescent layer It includes.

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 display device according to an exemplary embodiment of the present invention, FIG. 2 is a partial cross-sectional view of the electron emission display device illustrated in FIG. 1, and FIG. 3 is an electron according to an embodiment of the present invention. Partial plan view showing a main electrode, an isolation electrode and an electron emission portion of the emission device.

1 and 2, the electron emission display device includes a first substrate 10 and a second substrate 12 that are disposed to face each other in parallel at predetermined intervals. Sealing members (not shown) are disposed at the edges of the first substrate 10 and the second substrate 12 to join the two substrates, and the internal space is evacuated with a vacuum of approximately 10 ⁻⁶ torr. 10), the 2nd board | substrate 12 and the sealing member comprise 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 together with the first substrate 10, and the electron emission device The 100 is coupled to the second substrate 12 and the light emitting unit 110 provided on the second substrate 12 to form the electron emission display device 200.

First, cathode electrodes 14 serving as first driving electrodes are formed in a stripe pattern along one direction (y-axis direction in FIG. 1) of the first substrate 10, and the cathode electrodes ( The first insulating layer 16 is formed on the entire first substrate 10 while covering the 14. Gate electrodes 18, which are second driving electrodes, are formed on the first insulating layer 16 in a stripe pattern along a direction orthogonal to the cathode electrode 14 (the x-axis direction in FIG. 1).

In an exemplary embodiment of the present invention, an intersection area between the cathode electrode 14 and the gate electrode 18 forms one unit pixel.

The cathode electrode 14 has a main electrode 141 forming an opening 141a therein corresponding to each unit pixel, and an isolation electrode 142 spaced apart from the main electrode 141 inside the opening 141a. And a resistance layer 143 electrically connecting the main electrode 141 and the isolation electrode 142.

The isolation electrodes 142 are disposed in a line along one direction of the first substrate 10, for example, the length direction of the main electrode 141, inside the opening 141a. The main electrode 141 and the isolation electrode 142 may be made of a transparent material such as indium tin oxide (ITO) to form an electron emission unit to be described later through a back exposure method.

The resistance layer 143 may be formed as a pair on both sides of the isolation electrode 142, and formed to cover a portion of the top surface of the isolation electrode 142 to reduce contact resistance with the isolation electrode 142. The resistive layer 143 is indicated by a dotted line in FIG. 1.

The resistive layer 143 is a material having a specific resistance value of approximately 10,000 to 100,000 Ωcm, and has a resistance higher than that of a conventional conductive material constituting the main electrode 141 and the isolation electrode 142. For example, the p-type doped amorphous material It may be made of silicon.

In addition, the resistance layer 143 may be continuously formed along the longitudinal direction of the main electrode 141, or may be separately formed for each unit pixel. The openings 141a of the main electrode 141 may be formed for each unit pixel, but are not limited thereto. The number, shape, and number of isolation electrodes in the openings may be variously modified.

The electron emission part 20 is formed on the isolation electrode 142. The electron emission unit 20 may be formed of materials emitting electrons, for example, carbon-based materials or nanometer-sized materials when an electric field is applied in a vacuum. The electron emission unit 20 may include, for example, carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, fullerenes (C ₆₀ ), silicon nanowires, and combinations thereof.

On the other hand, the electron emission unit may be formed of a tip structure having a pointed tip mainly made of molybdenum (Mo) or silicon (Si).

Openings 161 and 181 corresponding to the electron emission parts 20 are formed in the first insulating layer 16 and the gate electrode 18 so that the electron emission parts 20 are exposed on the first substrate 10. do. In the drawing, the case where the electron emission unit 20 and the openings 161 and 181 are circular is illustrated, but the planar shape of the electron emission unit 20 and the openings 161 and 181 is not limited to the illustrated example, and may be a polygon or the like. It can be variously modified.

Also, in the present exemplary embodiment, the short width W _I of the isolation electrode 142 is greater than the long width W _G of the gate electrode opening 181 formed corresponding to the upper portion of the isolation electrode 142. (W _I ＞ W _G )

Here, the ratio W _I / W _G of the short width W _I of the isolation electrode 142 to the long width W _G of the gate electrode opening 181 is preferably 1.0 to 1.5. When the short width W _I ratio W _I / W _G of the isolation electrode 142 to the long width W _G of the gate electrode opening 181 exceeds 1.5, the degree of integration of the gate electrode opening 181 is inferior. Because there is a problem.

As illustrated in FIG. 3, the short width W _{I of the} isolation electrode 142 refers to the length of the short side when the isolation electrode 142 is formed in a rectangular shape, and the long width W of the gate electrode opening 181. As shown in FIG. 3, _G ) means a diameter when the gate electrode opening 181 is formed in a circular shape. In FIG. 3, the gate electrode opening 181 is indicated by a dotted line.

However, although not shown, when the gate electrode opening is formed in the long direction, the long width of the gate electrode will mean the length of the long side of the opening. That is, the shortest width of the isolation electrode 141 may be formed larger than the longest width of the gate electrode opening.

In addition, an individual area of the isolation electrode 142 may be larger than an individual area occupied by the gate electrode opening 181.

As described above, when the short width W _I of the isolation electrode 142 is larger than the long width W _G of the gate electrode opening 181, the isolation electrode 142 and the gate electrode opening 181 are aligned with each other. Even if this does not match, the probability that the end of the isolation electrode 142 may be exposed in the gate electrode opening 181 is reduced.

The focusing electrode 22 is formed on the gate electrodes 18 and the first insulating layer 16. A second insulating layer 24 is positioned below the focusing electrode 22 to insulate the gate electrodes 18 and the focusing electrode 22, and passes the electron beam through the second insulating layer 24 and the focusing electrode 22. Openings 241 and 221 are provided respectively. The openings 241 and 221 may be formed, for example, for each unit pixel so that the focusing electrode 22 comprehensively focuses electrons emitted from one unit pixel.

Next, on one surface of the second substrate 12 opposite to the first substrate 10, the fluorescent layer 26, for example, the red, green, and blue fluorescent layers 26R, 26G, and 26B may be separated from each other. It is formed at intervals, and a black layer 28 is formed between the fluorescent layers 26 to improve contrast of the screen. The fluorescent layer 26 may be disposed such that a fluorescent layer of one color corresponds to a unit pixel set on the first substrate 10.

An anode electrode 30 made of a metal film such as aluminum (Al) is formed on the fluorescent layer 26 and the black layer 28. The anode electrode 30 receives the high voltage necessary for accelerating the electron beam from the outside to maintain the fluorescent layer 26 in a high potential state, and visible light emitted toward the first substrate 10 of the visible light emitted from the fluorescent layer 26. Is reflected toward the second substrate 12 to increase the brightness of the screen.

The anode electrode may be formed of a transparent conductive film such as ITO. In this case, the anode electrode is positioned on one surface of the fluorescent layer 26 and the black layer 28 facing the second substrate 12. Moreover, the structure which forms simultaneously the above-mentioned transparent conductive film and a metal film as an anode electrode is also possible.

In addition, spacers 32 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 32 are positioned corresponding to the black layer 28 so as not to invade the fluorescent layer 26.

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 electrodes 22, and the anode electrodes 30 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 22 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 30 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 unit 20 in the unit pixels in which the voltage difference between the cathode electrode 14 and the gate electrode 18 is greater than or equal to a threshold, and electrons are emitted therefrom. The emitted electrons are focused through the opening 221 of the focusing electrode 22 to the center of the electron beam bundle, and are attracted to the fluorescent layer 26 of the corresponding unit pixel by being attracted by the high voltage applied to the anode electrode 30. It emits light.

In the above driving process, the electron emission display device according to the embodiment of the present invention improves the emission uniformity of the electron emission unit 20 by supplying a current to the electron emission unit 20 through the resistance layer 143, By forming the short width W _I of the isolation electrode 142 larger than the long width W _G of the gate electrode opening 181, an alignment mismatch occurs between the isolation electrode 142 and the gate electrode opening 181 during the manufacturing process. Even if the end of the isolation electrode 142 is not exposed to the outside can be suppressed electron beam distortion caused by the change in the electric field.

4 is a partial plan view illustrating a main electrode, an isolation electrode, and an electron emission unit of an electron emission device according to another exemplary embodiment of the present disclosure.

As shown in FIG. 4, the isolation electrode 144 has a hexagonal shape and its short width W _I is formed larger than the long width W _G of the gate electrode opening 181.

In short, the present invention is independent of their shape as long as the short width of the isolation electrode is formed to be larger than the long width of the gate electrode opening.

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 range of.

As described above, the electron emission display device according to the exemplary embodiment of the present invention forms a short width of the isolation electrode larger than the long width of the gate electrode opening, thereby reducing the probability that the end of the isolation electrode may be exposed in the gate electrode opening. Prevents electric field changes in the gate electrode openings. Accordingly, the electron emission display device reduces distortion of the electron beam due to a change in electric field, thereby preventing color purity from deteriorating and improving uniformity of emission per unit pixel.

Claims (11)

Board; A cathode electrode formed on the substrate; A gate electrode positioned to be insulated from the cathode electrode; And An electron emission unit electrically connected to the cathode electrode; The cathode electrode may include a main electrode forming an opening for each unit pixel set in the substrate, an isolation electrode disposed spaced apart from the main electrode inside the opening, and electrically connecting the main electrode and the isolation electrode on which the electron emission unit is placed. Consists of a resistive layer, The gate electrode has an opening corresponding to the isolation electrode to expose the electron emission part on a substrate. And the short width of the isolation electrode is W _I and the long width of the gate electrode opening is W _G , wherein the electron emission device satisfies the following relation. W _I ＞ W _G The method of claim 1, An electron emission device in which the short width of the isolation electrode and the long width of the gate electrode opening satisfy the following conditions. W _I / W _G = 1.0 ~ 1.5 The method of claim 1, And the individual area of said isolation electrode is formed larger than the individual area occupied by said gate electrode opening. The method of claim 1, And the gate electrode opening is formed in a circular shape. The method of claim 1, And the isolation electrode is formed in a rectangle or a hexagon. The method of claim 1, And the main electrode and the isolation electrode are made of a transparent material. The method of claim 1, The isolation electrodes are located in a line along the longitudinal direction of the main electrode, And the resistive layer is located on both sides of the isolation electrodes. The method of claim 7, wherein And one main electrode opening is formed for each of the unit pixels, and a plurality of isolation electrodes are formed in the main electrode opening. The method of claim 1, Further comprising a focusing electrode positioned to be insulated from the gate electrodes on the gate electrodes, And the focusing electrode forms one opening for passing an electron beam per unit pixel. The method of claim 9, 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, fullerenes (C ₆₀ ) and silicon nanowires. An electron emitting device according to any one of claims 1 to 10; Another substrate disposed to face the substrate; A fluorescent layer formed on one surface of the other substrate; And An anode formed on one surface of the fluorescent layer Electron emission display device comprising a.

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