KR20070083115A - 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 minimize a voltage drop effect of a cathode electrode by reducing effectively line resistance of the cathode electrode. An electron emission device includes a substrate(10), a plurality of cathode electrodes(14) formed on the substrate, a plurality of gate electrodes(18) insulated from the cathode electrodes, and electron emission units(22) connected electrically with the cathode electrodes. Each of the cathode electrodes includes a main electrodes(141), a plurality of isolation electrodes(142), and a resistance layer(143). The main electrode includes an aperture formed at a unit pixel on the substrate and is formed with a metal layer. The resistance layers are isolated from the main electrode within the aperture. The electron emission unit is positioned on one side of the isolation electrode. The isolation is formed with a transparent conductive layer. The resistance layer is formed to connect electrically the main electrode with the isolation 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 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 plan view of the cathode electrode illustrated in FIG. 1.

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, 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.

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, takes advantage of 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.

The electron-emitting device is applied with an unstable driving voltage to the electrode (hereinafter referred to as 'first electrode') that is electrically connected to the electron-emitting part and supplies a current required for electron emission when the electron-emitting device is in operation, or due to the line resistance of the first electrode. Differences may occur in the voltages applied to the electron emitters. In this case, the emission characteristics of the electron emission parts become nonuniform, leading to a decrease in uniformity of emission for each pixel.

In order to solve the above problem, an opening is formed in each unit pixel in the first electrode, the isolation electrodes are disposed inside the opening, an electron emission part is formed on each isolation electrode, and the first electrode and the isolation electrodes are formed as a resistive layer. A technology for uniformizing the emission characteristics of the electron emission parts through a resistance layer by connecting them 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 and the isolation electrodes are 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 line resistance of the first electrode is further increased.

Since the line resistance of the first electrode is difficult to compensate even with the resistive layer, the effect of uniformizing the emission by the resistive layer is lowered. As a result, in the conventional electron emission display device, a luminance difference occurs on the screen for each first electrode line due to the voltage drop of the first electrode, and this problem becomes more serious as the display screen becomes larger.

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 increase the uniformity of light emission of a display screen by reducing the line resistance of the first electrode. .

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

A substrate, cathode electrodes formed on the substrate, gate electrodes insulated from the cathode electrodes, and electron emission portions electrically connected to the cathode electrodes, each cathode electrode being formed per unit pixel on the substrate. A main electrode formed of a metal film forming an opening, spaced apart from the main electrode inside the opening, and having an electron emission part located on one surface thereof, a plurality of isolation electrodes made of a transparent conductive film, and electrically connecting the main electrode and the isolation electrodes. It provides an electron emission device comprising a resistive layer.

The main electrode may be formed to a greater thickness than the isolation electrodes.

The isolation electrodes may be positioned in a line along the length direction of the main electrode, and the resistance layer may be disposed covering both the top surface of the main electrode and a part of the top surface of the isolation electrodes on both sides of the isolation electrodes.

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 A main electrode including a fluorescent layer formed on one surface of the second substrate, an anode located on one side of the fluorescent layers, each cathode electrode being formed of a metal film with openings formed for each unit pixel on the first substrate; Provided is an electron emission display device comprising a plurality of isolation electrodes made of a transparent conductive film and an electron emission portion disposed on one surface thereof and spaced apart from the main electrode inside the opening, and a resistance layer electrically connecting the main electrode and the isolation electrodes. do.

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 the cathode electrode shown in FIG. 1.

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. An intersection area between the cathode electrode 14 and the gate electrode 18 constitutes one unit pixel.

In the present exemplary embodiment, each cathode electrode 14 has a stripe pattern and has a main electrode 141 having an opening 20 therein corresponding to each unit pixel, and a main electrode inside the opening 20. A plurality of isolation electrodes 142 spaced apart from 141 and a resistance layer 143 electrically connecting the main electrode 141 and the isolation electrodes 142 on both sides of the isolation electrodes 142. Include. In this case, the main electrode 141 is made of a metal film having excellent conductivity, and the isolation electrodes 142 are made of a transparent conductive film.

The main electrode 141 is connected to an external circuit (not shown) and has a driving voltage applied therefrom, and molybdenum (Mo), aluminum (Al), titanium (Ti), or platinum (PT) to minimize line resistance. It is made of a metal film excellent in conductivity as shown.

The isolation electrodes 142 may be disposed in a line along one direction of the first substrate 10, for example, along the length direction (y-axis direction of the drawing) of the main electrode 141, and the width of the main electrode 141 may be varied. Resistive layers 143 are positioned on both left and right sides of the isolation electrodes 142 along the direction (x-axis direction of the drawing).

An electron emission portion 22 is formed on each isolation electrode 142. The isolation electrodes 142 are made of a transparent conductive film such as ITO, and formed from the rear surface of the first substrate 10 when the electron emission portion 22 is formed. Ultraviolet rays are irradiated to apply the back exposure method to cure the electron-emitting material.

The resistance layer 143 may have a predetermined width and may be formed in a stripe pattern along the length direction of the main electrode 141, and may be formed to cover a portion of the upper surface of the main electrode 141 and the isolation electrodes 142. The contact resistance with the electrode 141 and the isolation electrodes 142 is reduced. The resistive layer 143 has a resistivity of about 10,000 to 100,000 Ωcm and may be formed of, for example, p-type or n-type doped amorphous silicon.

The main electrode 141 can lower the line resistance due to the excellent conductive characteristics of the metal film even though the effective width (the electrode width that substantially contributes to the current flow in the unit pixel) is reduced by the opening 20. More preferably, the main electrode 141 is formed to a larger thickness than the isolation electrodes 142 to maximize the effect of reducing the line resistance.

In the structure of the cathode electrode 14 of the present embodiment described above, the line resistance of the cathode electrode 14 is effectively reduced without using a separate auxiliary electrode for reducing the resistance.

The electron emitter 22 disposed on the isolation electrodes 142 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 20 may include, for example, at least one material of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, fullerenes (C ₆₀ ), and silicon nanowires.

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 electrodes 18 to expose the electron emission parts 22 on the first substrate 10. . In the drawing, although the electron emitter 22 and the openings 161 and 181 are circular, the planar shape of the electron emitter 22 and the openings 161 and 181 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 collect electrons emitted from each electron emission unit 22, or forms one opening 241 for each unit pixel. The electrons emitted from the unit pixels of may be comprehensively focused. 1 shows the second case.

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. The fluorescent layer 28 is disposed so that the fluorescent layers 28R, 28G, and 28B of one color correspond to the unit pixels set on the first substrate 10.

An anode electrode 32 made 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 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 cathode electrode 14 is reduced. As the line resistance is minimized, the voltage drop is minimized to improve the uniformity of light emission and the luminance uniformity of the entire screen of the cathode electrode 14.

The following table shows the electron emission display device of the comparative example in which the main electrode and the isolation electrodes are both made of an ITO conductive film, and the main electrode in the electron emission display device of the present embodiment, wherein the main electrode and the isolation electrodes are made of a chromium conductive film and an ITO conductive film, respectively. It shows the line resistance according to the thickness change. The electron emission display device of the comparative example and the electron emission display device of the example which were used for the experiment consist of the same structure except the material of a main electrode.

As shown in the table, the cathode of the embodiment in which the main electrode was formed of the metal film showed a lower line resistance than the cathode of the comparative example having the same thickness of the main electrode.

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 of the present invention effectively reduces the line resistance of the cathode electrode to minimize the voltage drop of the cathode electrode. Accordingly, the electron emission display device according to the present invention can increase the uniformity of emission for each cathode electrode line, thereby ensuring excellent luminance uniformity over the entire display screen.

Claims (7)

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 formed of a metal film with openings formed in unit pixels on the substrate; A plurality of isolation electrodes spaced apart from the main electrode inside the opening and positioned at one surface thereof with the electron emission part formed of a transparent conductive film; And A resistive layer electrically connecting the main electrode and the isolation electrode. Electron emitting device comprising a. The method of claim 1, And the main electrode has a thickness greater than the isolation electrodes. The method of claim 1, And the isolation electrodes are positioned in a line along the longitudinal direction of the main electrode. The method of claim 3, And the resistance layer is located on both sides of the isolation electrodes, covering the top surface of the main electrode and a portion of the top surface of the isolation electrodes. The method of claim 1, And a focusing electrode overlying the cathode and gate electrodes and insulated from the cathode and gate electrodes. 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, fullerenes (C ₆₀ ) and silicon nanowires. An electron emitting device according to any one of claims 1 to 6; 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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