KR20070111662A - 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 intensify a focusing force of the electron beam emitted from an electron emission portion by forming a resistive layer at a position higher than the electron emission portion. Cathode electrodes(14) are formed on a substrate(10), and gate electrodes(18) are formed on the cathode electrodes in insulation relation. Electron emission portions(22) are electrically connected to the cathode electrodes. An insulating layer(24) is formed on the cathode electrodes and the gate electrodes, and has an opening(241) through which electron beam passes. Focuss electrodes(26) are positioned on the cathode electrode, and extend into an inner wall of the opening. Each cathode electrode has primary electrodes(141) having an opening every unit pixel, isolated electrodes(142) spaced apart from the primary electrodes in the opening, and a resistive layer(143) electrically connecting the primary electrodes with the isolated electrodes.

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 a first 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 cross-sectional view of an electron emission display device according to a second embodiment of the present invention.

The present invention relates to an electron emission device and an electron emission display device using the same, and more particularly, to a focusing electrode that focuses an electron beam emitted from an electron emission unit.

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 a cold cathode is a field emitter array (FEA) type, a surface conduction emission (SCE) type, a metal-insulating layer-metal -Metal (MIM) type and Metal-Insulator-Semiconductor (MIS) type and the like 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 above electron emission display device, the electron beam emitted from the electron emission portion tends to spread toward the fluorescent layer due to distortion of the equipotential line or the like. According to the path of the electron beam, some of the electrons do not reach the desired fluorescent layer, but reach a fluorescent layer of another color adjacent thereto to emit light, which causes a decrease in color purity and contrast characteristics of the electron emission display device.

In order to improve this problem, a focusing electrode has been proposed as one of means for electron beam control. However, since the focusing electrode is generally formed as a thin film of several micrometers (μm), there is a limit in applying a sufficient electric field to the electron beam passing through the focusing electrode, and there is a problem in that some electron beams are refracted to generate secondary light emission. .

On the other hand, the electron emission display device is applied with an unstable driving voltage to an electrode (hereinafter, referred to as a 'first electrode' for convenience) that is electrically connected to the electron emission unit and supplies a current required for electron emission during driving, or Line resistance can cause differences in the voltage applied to the electron emitters. 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 problem, a structure for uniformizing the emission characteristics of the electron emitting units by supplying a current to the electron emitting units through the resistive layer has been proposed and used. In the electrode structure having such a resistive layer, the amount of emission current of the electron emission portion is lowered as a whole, so the necessity of electron beam focusing is more urgent.

Accordingly, an object of the present invention is to provide an electron emission device and an electron emission display device using the same to secure emission uniformity and to enhance the focusing force of an electron beam.

In order to achieve the above object, an electron emission device according to an exemplary embodiment of the present invention includes a substrate, cathode electrodes formed on the substrate, gate electrodes positioned to be insulated from the cathode electrodes, and electrically connected to the cathode electrode. An electron emitting portion, an insulating layer formed on the cathode electrodes and the gate electrodes and having an opening for passing an electron beam, and a focusing electrode positioned on the insulating layer and extending to an inner wall of the opening of the insulating layer, The cathode electrode may include a main electrode having an opening for each unit pixel set in the substrate, an isolation electrode disposed to be spaced apart from the main electrode inside the opening, and to electrically connect the main electrode and the isolation electrode on which the electron emission unit is placed. And a resistive layer.

In addition, the focusing electrode may extend to the inner wall of the opening of the insulating layer to satisfy the following conditions.

L2 / L1 ≤ 1/2

Here, L1 means the thickness of the insulating layer, L2 means the length of the focusing electrode extending to the inner wall of the opening of the insulating layer.

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, the resistance layer may be formed higher than the height of the electron emitting portion while in side contact with the electron emitting portion.

In addition, the isolation electrode may be formed of a transparent conductive film, and the main electrode may be formed of aluminum (Al), molybdenum (Mo), titanium (Ti), tungsten (W), and an alloy thereof.

In addition, the focusing electrode may form one opening for passing an electron beam per unit pixel.

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 exemplary embodiment of the present invention may be formed on the electron emission device, the other substrate disposed to face the substrate, the fluorescent layers formed on one surface of the other substrate, and one surface of the fluorescent layers. An anode electrode is included.

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 a first embodiment of the present invention, and FIG. 2 is a partial cross-sectional view of the electron emission display device shown in FIG.

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 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 together with the first substrate 10, and the electron emission device ( 100 is combined with the second substrate 12 and the light emitting unit 110 provided on the second substrate 12 to form an electron emission display device.

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 includes a main electrode 141 forming an opening 141a therein corresponding to each unit pixel, and a plurality of isolation electrodes spaced apart from the main electrode 141 inside the opening 141a. 142 and a resistance layer 143 electrically connecting the main electrode 141 and the isolation electrodes 142.

The isolation electrodes 142 are positioned in one line along the length direction (y-axis direction in FIG. 1) of the first substrate 10, for example, the main electrode 141, inside the opening 141a. The isolation electrode 142 is formed of a transparent conductive film such as ITO so as to form an electron emission portion to be described later by backside exposure, and the main electrode 141 is formed of aluminum (Al), molybdenum (Mo), which have lower resistance than ITO, and It may be formed of titanium (Ti), tungsten (W) and alloys thereof.

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 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.

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. In addition, one opening 141a of the main electrode 141 may be formed for each unit pixel, but is not limited thereto, and the number, shape, and number of isolation electrodes in the opening may be variously modified.

The electron emission part 22 is formed on the isolation electrode 142. The electron emission unit 22 may be formed of materials emitting electrons when a electric field is applied in a vacuum, such as a carbon-based material or a nanometer-sized material. The electron emission unit 22 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 22 are formed in the first insulating layer 16 and the gate electrode 18 so that the electron emission parts 22 are exposed on the first substrate 10. do. In the drawing, the case where the electron emitter 22 and the openings 161 and 181 are circular is illustrated. However, the planar shape of the electron emitter 22 and the openings 161 and 181 is not limited to the illustrated example and may be a polygon. It can be variously modified.

A second insulating layer 24 is formed on the gate electrodes 18 and the first insulating layer 16, and the second insulating layer 24 is provided with an opening 241 for passage of the electron beam. For example, one second insulating layer opening 241 may be formed for each unit pixel. In addition, a focusing electrode 26 is formed on the second insulating layer 24 to focus the electron beam passing through the second insulating layer opening 241.

The focusing electrode 26 according to the present exemplary embodiment extends not only to the upper surface of the second insulating layer 24 but also to the inner wall of the opening 241 of the second insulating layer 24. The focusing electrode 24 may extend until not shorted with the gate electrode 18, but preferably extends to the inner wall of the opening 241 of the insulating layer 24 to satisfy the following conditions.

L2 / L1 ≤ 1/2

Here, L1 denotes a thickness of the second insulating layer 24, and L2 denotes a length of the focusing electrode 26 extending to an inner wall of the opening 241 of the second insulating layer 24.

In this way, the focusing electrode 26 extends to the length L2 less than half the thickness L1 of the second insulating layer 24, and the extended length L2 of the focusing electrode 26 is the thickness L1 of the second insulating layer 24. In order to prevent this, the electron beam is more likely to be over-focused.

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.

In addition, an anode electrode 32 formed of a metal film such as aluminum (Al) is formed on one surface of the fluorescent layer 28 and the black layer 30. The anode 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.

The anode electrode may be formed of a transparent conductive film such as indium tin oxide (ITO). In this case, the anode electrode is positioned on one surface of the fluorescent layer 28 and the black layer 30 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 34 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 configuration is driven by supplying a predetermined voltage to the cathode electrode 14, the gate electrode 18, the focusing electrode 26, and the anode electrode 32 from the outside.

For example, any one of the cathode electrode 14 and the gate electrode 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. The focusing electrode 26 receives a voltage required for focusing, for example, 0 V or a negative DC voltage of several to several tens of volts, and the anode electrode 32 is a voltage necessary for accelerating the electron beam, for example, several hundred to several thousand volts. DC voltage is applied.

As a result, an electric field is formed around the electron emission unit 22 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 to the center of the electron beam bundle while passing through the focusing electrode 26, and are attracted by the high voltage applied to the anode electrode 32 to collide with the fluorescent layer 28 of the corresponding unit pixel to emit light.

In the above-described driving process, the resistance layer 143 may apply a driving voltage equalized to the electron emission parts 22 to equalize the emission characteristics of the electron emission parts 22, and thus, the second insulating layer 24 may be formed. The focusing electrode extending to the inner wall of the opening 241 enhances the focusing force of the electron beam passing through the opening 241 to further impart linearity to the electron beam.

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

As shown in FIG. 3, the cathode electrode 44 is composed of a main electrode 441, an isolation electrode 442, and a resistive layer 443, and the resistive layer 443 is in side contact with the electron emission part 22. It is formed to be. In this case, the resistance layer 443 may be formed higher than the electron emission unit 22 to enhance the focusing force of the electron beam emitted from the electron emission unit 22.

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 device according to the embodiment of the present invention improves the cathode electrode structure and the structure of the focusing electrode, thereby uniformly forming the emission characteristics of the electron emission portion, and enhances the focusing force of the electron beam. Accordingly, the electron emission display device according to the exemplary embodiment of the present invention improves luminance uniformity and improves color purity and contrast characteristics when implementing a large area.

Claims (9)

Board; Cathode electrodes formed on the substrate; Gate electrodes positioned to be insulated from the cathode electrodes; Electron emission parts electrically connected to the cathode electrode; An insulating layer formed on the cathode electrodes and the gate electrodes and having an opening for passing an electron beam; And A focusing electrode positioned on the insulating layer and extending to an inner wall of the opening of the insulating layer, The cathode electrode may include a main electrode having an opening for each unit pixel set in the substrate, an isolation electrode disposed to be spaced apart from the main electrode inside the opening, and to electrically connect the main electrode and the isolation electrode on which the electron emission unit is placed. An electron emitting device comprising a resistive layer. The method of claim 1, And the focusing electrode extends to the inner wall of the opening of the insulating layer so as to satisfy the following condition. L2 / L1 ≤ 1/2 Here, L1 means the thickness of the insulating layer, L2 means the length of the focusing electrode extending to the inner wall of the opening of the insulating layer. 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 3, And the resistive layer is formed higher than the height of the electron emitting portion while in lateral contact with the electron emitting portion. The method of claim 1, And the isolation electrode is formed of a transparent conductive film. The method of claim 5, And the main electrode is formed of aluminum (Al), molybdenum (Mo), titanium (Ti), tungsten (W) and alloys thereof. The method of claim 1, And the focusing electrode forms one opening for passing an electron beam per unit pixel. 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, fullerenes (C ₆₀ ) and silicon nanowires. An electron emitting device according to any one of claims 1 to 8; Another substrate disposed to face the substrate; Fluorescent layers formed on one surface of the other substrate; And An anode formed on one surface of the fluorescent layers Electron emission display device comprising a.

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