KR20070046515A - Electron emission device and electron emission display device using the same - Google Patents

Abstract

The present invention relates to an electron emission device having an improved electrode structure and an electron emission display device using the same in order to reduce the line resistance of the electrode. The electron emission device according to the present invention includes a substrate, cathode electrodes formed on the substrate, gate electrodes positioned insulated from the cathode electrodes, and electron emission portions electrically connected to the cathode electrode. In this case, each of the cathode electrodes may include a main electrode forming an opening for each unit pixel set in the substrate, a plurality of isolation electrodes positioned apart from the main electrode inside the opening, and having an electron emission part, and electrically connecting the main electrode and the isolation electrodes. And a plurality of auxiliary electrodes at least partially in contact with the resistive layer and located in different layers from the substrate.

Cathode electrode, gate electrode, electron emission part, resistive layer, main electrode, isolation electrode, auxiliary electrode

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.

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

3 is a partial plan view of a cathode electrode and a gate electrode in an electron emission display device according to an exemplary embodiment of the present invention.

4 is a partial plan view of a cathode electrode illustrating a modification of the first auxiliary 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 having an improved electrode structure in order to reduce line resistance of an electrode, and an electron emitting display device using the same.

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.

The field emission array (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. The use of low or high aspect ratio materials, such as carbon nanotubes and carbon-based materials such as graphite and diamond-like carbon, utilizes the principle that electrons are easily released by an electric field in 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 an electrode (hereinafter, referred to as a 'first electrode' for convenience) to be electrically connected to the electron emission unit to supply a current required for electron emission, 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 problem, openings are formed for each unit pixel in the first electrode, isolation electrodes are formed inside the opening, electron emission portions are formed on each isolation electrode, and the first electrode and the isolation electrodes are connected by a resistive layer. A technique for uniformizing the emission characteristics of the electron emission parts through the resistive layer has been proposed and used.

However, in the above-described structure, the first electrode is compared with the first electrode without the opening due to not only the internal resistance of the first electrode itself but also a reduction in the effective width (the electrode width that substantially contributes to the current flow in the unit pixel) due to the openings. You will have greater line resistance.

Furthermore, when the first electrode is formed of a transparent conductive film such as indium tin oxide (ITO) in order to apply a so-called backside exposure method of curing an electron emission material by irradiating ultraviolet rays from the rear surface of the substrate when forming the electron emission portion, the first electrode The line resistance of the electrode becomes higher.

Since the line resistance of the first electrode is difficult to compensate even with the resistive layer, the effect of the uniformity of the emission due to the resistive layer is lowered. As a result, in the conventional electron emission display device, the voltage drop of the first electrode causes the length direction of the first electrode. Accordingly, there is a problem in that the uniformity of emission of the fluorescent layer is lowered.

Therefore, the present invention is to solve the above problems, an object of the present invention is to reduce the line resistance of the first electrode to increase the uniformity of emission of the fluorescent layer in the direction of the first electrode and the electron emission device using the same It is to provide a display device.

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

A unit pixel including a substrate, cathode electrodes formed on the substrate, gate electrodes insulated from the cathode electrodes, and electron emission parts electrically connected to the cathode electrodes, wherein each cathode electrode is set on the substrate. A main electrode forming an opening each time, a plurality of isolating electrodes which are spaced apart from the main electrode inside the opening, and in which an electron emission part is placed, a resistance layer electrically connecting the main electrode and the isolation electrodes, and at least a portion of the resistance layer; Provided is an electron emitting device comprising a plurality of auxiliary electrodes in contact and located in different layers from a substrate.

The auxiliary electrodes include a first auxiliary electrode formed on the main electrode and the isolation electrodes, and a second auxiliary electrode formed on the resistance layer.

The first auxiliary electrode may be formed on the entire upper surface of the main electrode and the isolation electrodes except for the electron emission part forming portion, or may be formed in a pair of stripe patterns along the length direction of the main electrode on the main electrode.

The resistance layer and the second auxiliary electrode may be formed in a stripe pattern along the length direction of the main electrode on both left and right sides of the isolation electrodes along the width direction of the main electrode, and the second auxiliary electrode may be formed at one end of the main electrode. And any one of the first auxiliary electrode and the first auxiliary electrode.

The first auxiliary electrode may be formed of chromium or molybdenum, and the second auxiliary electrode may be formed of aluminum or silver.

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, gate electrodes positioned to be insulated from the cathode electrodes, electron emission parts electrically connected to the cathode electrodes, and 2, a phosphor electrode formed on the substrate, an anode electrode formed on one surface of the phosphor layers, each cathode electrode forming an opening for each unit pixel set in the substrate, and spaced apart from the main electrode inside the opening. A plurality of isolating electrodes positioned and positioned with electron emission, a resistive layer electrically connecting the main electrode and the isolating electrode, and a plurality of auxiliary electrodes at least partially in contact with the resistive layer and located on different layers from the substrate. It provides an electron emission display device.

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, and FIG. 3 is a partial plan view of a cathode electrode and a gate electrode.

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 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, 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 above, an intersection area between the cathode electrode 14 and the gate electrode 18 forms one unit pixel. Each of the cathode electrodes 14 may include a main electrode 141 forming an opening 20 therein corresponding to each unit pixel, and a plurality of cathode electrodes 14 spaced apart from the main electrode 141 inside the opening 20. The isolation electrodes 142 are formed between the main electrode 141 and the isolation electrodes 142 to electrically connect the two electrodes.

The isolation electrodes 142 are located in a line along the longitudinal direction of the main electrode 141 in one direction of the first substrate 10, for example, inside the opening 20, and emit electrons over each isolation electrode 142. The part 22 is formed. In addition, the resistance layers 143 are positioned on both left and right sides of the isolation electrodes 142 along the width direction of the main electrode 141.

The resistive layer 143 has a resistivity of approximately 10,000 to 100,000 Ωcm, and has a larger resistance than the conductive material forming the main electrode 141 and the isolation electrodes 142. For example, the resistive layer 143 may be formed of p-type doped amorphous silicon. Can be done. The resistance layer 143 has a predetermined width and is formed in a stripe pattern along the longitudinal direction of the main electrode 141, and is formed to cover a portion of the upper surface of the main electrode 141 and the isolation electrodes 142. 141 and the contact resistance with the isolation electrodes 142 is reduced. The resistive layer 143 may be formed to have a thickness of approximately 2,000 mW.

In this embodiment, the cathode electrode 14 further includes two auxiliary electrodes 144 and 145 at least partially in contact with the resistive layer 143 and positioned on different layers to reduce the line resistance. More specifically, the first auxiliary electrode 144 having a lower resistance than the main electrode 141 is formed on the main electrode 141 and the isolation electrodes 142, and also has a lower resistance than the main electrode 141. The second auxiliary electrode 145 is formed on the resistance layer 143 to reduce the line resistance of the main electrode 141.

The main electrode 141 and the isolation electrodes 142 may be formed of a transparent conductive film such as ITO, and the first auxiliary electrode 144 may be a metal material having a lower resistance than that of ITO, for example, chromium (Cr) or molybdenum (Mo). It can be made of). The first auxiliary electrode 144 is formed of a material that does not cause galvanic phenomenon with the main electrode 141, the isolation electrodes 142, and the resistive layer 143 in the manufacturing process, and does not damage the ITO etchant and the resistive layer etchant. Should be. Examples of the metal material satisfying this condition include chromium and molybdenum described above.

The first auxiliary electrode 144 is formed on the entire upper surface of the main electrode 141 and the isolation electrodes 142, or is isolated from the main electrode 141 except for the electron emission part 22 formation region as shown in FIG. 2. It may be formed on the entire upper surface of the electrodes 142. In addition, as illustrated in FIG. 4, the pair of first auxiliary electrodes 144 ′ may be formed in a stripe pattern on the main electrode 141 along the length direction of the main electrode 141.

The second auxiliary electrode 145 may be made of a metal material having excellent conductivity, for example, aluminum (Al) or silver (Ag). The second auxiliary electrode 145 should be formed of a metal material in which the second auxiliary electrode etchant does not affect the resistance layer 143, the first auxiliary electrode 144, the main electrode 141, and the isolation electrodes 142. In addition, the above-mentioned aluminum and silver are mentioned as a metallic material which satisfy | fills this condition.

The second auxiliary electrode 145 may be formed in the same stripe pattern as that of the resistance layer 143 on the resistance layer 143, and may be formed at one end of the main electrode 141 to which the driving voltage is applied. 1 may be in contact with the auxiliary electrode 144. Meanwhile, the second auxiliary electrode 145 may be formed on the resistance layer 143 without contacting the main electrode 141 or the first auxiliary electrode 144, and in this case, the second auxiliary electrode 145 may be formed of a resistance layer ( Since it is electrically connected to the first auxiliary electrode 144 through 143, it serves as an auxiliary electrode for lowering the line resistance of the main electrode 141.

The electron emission unit 22 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 22 may include, for example, carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, 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 to expose the electron emission parts 22 on the first substrate 10. Be sure to In the drawing, the case where the electron emitter 22 and the openings 161 and 181 are circular is illustrated, but the planar shape of the electron emitter and the opening is not limited to the illustrated example.

The 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 disposed under the focusing electrode 24 to insulate the gate electrodes 18 and the focusing electrode 24, and also passes the electron beam through the focusing electrode 24 and the second insulating layer 26. Openings 241 and 261 are provided.

The focusing electrode 24 forms an opening corresponding to each of the electron emission units 22 to individually focus electrons emitted from each electron emission unit 22, or to form one opening for each unit pixel. The electrons emitted from the unit pixel may be collectively focused. In FIG. 1, the latter case is illustrated.

Next, a fluorescent layer 28, for example, red, green, and blue fluorescent layers are formed on one surface of the second substrate 12 opposite to the first substrate 10 at random intervals, and each fluorescent The black layer 30 is formed between the layers 28 to improve the contrast of the screen. The fluorescent layer 28 is disposed so that the fluorescent layer of one color corresponds to the unit pixel set on the first substrate 10.

An anode electrode 32 formed of a metal film such as aluminum (Al) 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.

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 (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.

Then, an electric field is formed around the electron emission part 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 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 are attracted to the fluorescent layer 28 of the corresponding unit pixel by being attracted by the high voltage applied to the anode electrode 32. It emits light.

In the above-described driving process, the resistive layer 143 allows the driving voltages of the same conditions to be applied to the electron emission parts 22 to uniform the emission characteristics of the electron emission parts 22, and the first auxiliary electrode 144. The second auxiliary electrode 145 reduces the line resistance of the main electrode 141 to minimize the voltage drop of the cathode electrode 14. Accordingly, the electron emission display device of the present exemplary embodiment may implement uniform screen luminance along the length direction of the cathode electrode 14.

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 of the present invention can minimize the voltage drop of the cathode by reducing the line resistance of the cathode through the first auxiliary electrode and the second auxiliary electrode. Accordingly, the electron emission display device according to the present invention improves display uniformity by increasing the light emission uniformity of the fluorescent layers along the length direction of the cathode electrode.

Claims (11)

A substrate; Cathode electrodes formed on the substrate; Gate electrodes positioned to be insulated from the cathode electrodes; And And electron emission parts electrically connected to the cathode electrode, Each of the cathode electrodes, A main electrode forming an opening for each unit pixel set in the substrate; A plurality of isolation electrodes disposed in the opening and spaced apart from the main electrode and on which the electron emission portions are placed; A resistance layer electrically connecting the main electrode and the isolation electrode; And And a plurality of auxiliary electrodes at least partially in contact with the resistive layer and located in different layers from the substrate. The method of claim 1, And an auxiliary electrode formed on the main electrode and the isolation electrodes, and a second auxiliary electrode formed on the resistive layer. The method of claim 2, And the first auxiliary electrode is formed on the entire upper surface of the main electrode and the isolation electrodes except for the electron emission portion forming portion. The method of claim 2, And the first auxiliary electrode is formed in a pair of stripe patterns along the longitudinal direction of the main electrode on the main electrode. The method of claim 2, And the first auxiliary electrode is formed of any one of chromium (Cr) and molybdenum (Mo). The method of claim 2, And the resistance layer and the second auxiliary electrode are formed in a stripe pattern along the longitudinal direction of the main electrode on both left and right sides of the isolation electrodes along the width direction of the main electrode. The method of claim 6, And the second auxiliary electrode contacts one of the main electrode and the first auxiliary electrode at one end of the main electrode. The method of claim 2, And the second auxiliary electrode is formed of any one of aluminum (Al) and silver (Ag). The method of claim 1, And a focusing electrode positioned above the gate electrodes and insulated from the gate electrodes and forming an opening for passing an electron beam. 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. An electron emitting device according to any one of claims 1 to 10; 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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