KR20070115439A - 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 decrease line resistance for a cathode electrode by maximumly reducing a loss region of the cathode electrode for one electron emission portion. A cathode electrode(14) with a first opening(141) is formed on a substrate(10). A resistive layer(20) with a second opening(201) is formed on the substrate to cover the cathode electrode. An electron emission portion(22) is disposed in the first and second openings, and is electrically connected to the resistive layer. The cathode electrode has a stripe pattern which is formed in a cross direction of the substrate, and the resistive layer has a pattern corresponding to the pattern of the cathode electrode.

Description

Electron emission device and electron emission display device using the same {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 plan view of main parts of an electron emission display device according to an exemplary embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron emission device and an electron emission display device using the same. More particularly, the electron emission device and the electron emission display device using the same can easily control the resistance value of the resistance layer uniformly controlling the electron emission emission characteristics. It is about.

In general, electron emission elements are 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 FEA type electron emission element includes an electron emission portion and a cathode electrode and a gate electrode as driving electrodes for controlling electron emission of the electron emission portion. Here, the electron emitting portion may be a material having a low work function or a high aspect ratio, for example, a tip structure having a sharp tip, mainly made of molybdenum (Mo) or silicon (Si), or carbon nanotubes, graphite, and diamond. It can be constructed using carbon-based materials such as phase carbon, which utilize the principle of easily emitting electrons by an electric field in vacuum.

On the other hand, the electron emission elements are formed in an array on one substrate to form an electron emission device, and the electron emission device is combined with another substrate having a light emitting unit composed of a fluorescent layer and an anode electrode to emit electrons. A display device (electron emission display device) is constituted.

In the electron emission device, an electrode electrically connected to an electron emission unit and supplying a current required for electron emission is called a cathode electrode. When a driving voltage is applied to the cathode, electrons are emitted from the electron emission unit by the electric field. In this case, when an unstable voltage is applied to the cathode electrode or a voltage drop occurs to the cathode electrode, a difference may occur in the voltage applied to the electron emission units of each pixel. As a result, the emission current amount of each of the electron emission parts is not constant, thereby causing a problem of lowering the uniformity of emission for each pixel.

In order to solve the above problem, the number of electron emission portions is increased for each unit pixel or a resistance layer is formed between the cathode electrode and the electron emission portion so that the resistance layer controls the amount of emission current of the electron emission portions. In the latter case, it is classified into a vertical structure and a horizontal structure according to the direction of the current flowing from the cathode electrode to the electron emission portion with the resistance layer interposed therebetween.

In the vertical structure, a resistance layer is formed in a direction perpendicular to the cathode electrode and the electron emission portion to apply an individual resistance to the electron emission source. However, the vertical structure has a problem in that the entire lower surface of the electron emission source is in contact with the resistive layer and thus is affected by the material forming the resistive layer during resistance control.

In the horizontal structure, when the cathode is separated into a main electrode to which a driving voltage is applied and an isolation electrode where an electron emission portion is located, a resistance layer is formed between the main electrode and the isolation electrodes on both sides of the isolation electrodes to form an electron emission portion. Apply an individual resistor.

However, such a structure has a resistance layer in contact with a plurality of isolation electrodes so that adjacent isolation electrodes are electrically connected through the resistance layer, so that current flow occurs between the isolation electrodes through the resistance layer, thereby reducing the characteristics of the individual resistors. There is a problem.

For example, when an excessive amount of emission current is present in an electron emission portion located in one of two neighboring isolation electrodes, the isolation electrode causes a voltage rise by the resistive layer to stabilize the emission current. In this process, when current flows through the resistive layer between the isolation electrode and the neighboring isolation electrode maintaining the 0V potential, the characteristics of the individual resistors are reduced, which causes difficulty in controlling the amount of emission current for each electron emission unit.

In addition, by securing a pattern for separating the main electrode and the isolation electrode, there is a problem in that the line width of the cathode electrode is reduced and the line resistance is increased.

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 easily adjust an individual resistance value for each electron emission unit.

An electron emission device according to an embodiment of the present invention for achieving the above object, the substrate, having a first opening and a cathode electrode formed on the substrate, and a second opening corresponding to the first opening while covering the substrate A resistive layer formed thereon, and an electron emission portion disposed in the first and second openings and electrically connected to the resistive layer.

The electron emission portion is formed in direct contact with the substrate.

The first opening and the second opening are circular, particularly concentric, and the diameter of the second opening is smaller than the diameter of the first opening.

The cathode electrode is formed of a metal, and the resistance layer is formed of amorphous silicon.

The cathode electrode has a stripe pattern and is formed along one direction of the substrate, and the resistance layer is formed along the cathode electrode with a pattern corresponding to the pattern of the cathode electrode.

Further, the resistive layer is in direct contact with the electron emitting portion while being disposed in the first opening.

Meanwhile, an electron emission display device according to a preferred embodiment of the present invention includes a first substrate and a second substrate disposed opposite to each other, an electron emission unit formed on the first substrate, and a light emitting unit formed on the second substrate. The electron emission unit includes a cathode electrode formed on a first substrate having a first opening, a resistance layer formed on the first substrate covering a cathode electrode having a second opening corresponding to the first opening, and a first opening and a second opening. An electron emission portion disposed in the opening and electrically connected to the resistive layer.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail.

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. 3 is a plan view of main parts of an electron emission display device according to an exemplary embodiment of the present invention.

1 and 2, the electron emission display device includes a first substrate 10 and a second substrate 12 disposed to face each other in parallel with each other at a predetermined interval. The first substrate 10 and the second substrate 12 are joined by a sealing member (not shown) disposed at an edge thereof to constitute a container having an internal space. This vessel is configured as a vacuum vessel by keeping the internal space at a vacuum degree of approximately 10 ^-6 Torr.

On the surface of the first substrate 10 facing the second substrate 12, electron emission elements are arranged in an array to form an electron emission device 100 together with the first substrate 10, and the electron emission device 100. Constitutes an electron emission display device together with the second substrate 12 and the light emitting unit 110 provided on the second substrate 12.

Hereinafter, the electron emission display device will be described in detail. First, the cathode electrodes 14 are formed on the first substrate 10 along the one direction (y-axis direction in FIG. 1) of the first substrate 10. Is formed.

The first insulating layer 16 is formed on the entire first substrate 10 while covering the cathode electrodes 14, and the gate electrodes 18 are orthogonal to the cathode electrode 14 on the first insulating layer 16. It is formed in a stripe pattern along the (x-axis direction in Fig. 1).

As a result, an intersection region of the cathode electrode 14 and the gate electrode 18 is formed, and the intersection region may constitute one unit pixel.

In the present embodiment, the cathode electrode 14 includes at least one first opening 141 for each unit pixel.

The resistive layer 20 is formed on the cathode electrode 14 to cover the first substrate 10 exposed through the cathode electrode 14 and the first opening 141. A second opening 201 is provided to expose the first substrate 10 in the opening 141.

The first openings 141 are formed in plural in a predetermined form for each unit pixel of the cathode electrode 14. Specifically, the first opening 14 is formed of a circular opening that is the same as the shape of the electron emitting portion 22 to be described later, and the diameter thereof is preferably larger than the diameter of the electron emitting portion 22.

However, in the present invention, the shape of the first opening 141 is not limited thereto, and may be modified according to the shape of the electron emission unit 22.

The resistive layer 20 is formed on the cathode electrode 14 and the first substrate 10 to cover the first substrate 10 exposed through the cathode electrode 14 and the first opening 141. The resistance layer 20 may be formed along the cathode electrode 14 to correspond to the pattern of the cathode electrode 14, or may be formed according to the pattern of the unit pixel.

The resistance layer 20 has a step corresponding to the thickness of the cathode electrode 14. That is, as shown in FIG. 2, since the resistive layer 20 has a uniform thickness and is formed on the cathode electrode 14 and the first substrate 10, the resistive layer 20 of the resistive layer 20 positioned on the cathode electrode 14 is formed. The portion is positioned relatively higher than the portion of the resistive layer 20 positioned on the first substrate 10.

In addition, the resistance layer 20 may be formed of a material having a specific resistance value of approximately 10,000 to 100,000 OMEGA cm and may have a larger resistance than the cathode electrode 14 that is typically formed of a conductive material. In one example, the resistive layer may be formed of p-type or n-type doped amorphous silicon.

A part of the resistive layer 14, that is, the resistive layer 20 formed in the first opening 141, is formed with a second opening 201 concentric with the first opening 14. Here, it is preferable that the second opening 201 is relatively narrow in comparison with the width of the first opening 141. In the second opening 201, an electron emission unit 22, which will be described later, is formed on the first substrate 10 while contacting the resistive layer 20.

As such, the resistance layer 20 electrically connected to the electron emitter 22 controls the current flowing from the cathode electrode 14 to the electron emitter 22, wherein the cathode electrode 14 is located in the first opening. ) And the width (see W in FIG. 3) of the resistive layer 20 positioned between the electron emitter 22 is a reference for calculating the resistance value of the resistive layer 20 for each electron emitter 22. Can be. That is, the resistance value can be adjusted according to the width W. The width W may be adjusted for each cathode of one cathode electrode 14 or for each electron emission portion of one unit pixel.

According to the present exemplary embodiment, the resistive layer 20 formed as described above has a so-called horizontal structure and forms an electrical connection structure with the cathode electrode 14 and the transfer emitter 22.

The resistive layer 20 is electrically connected to the electron emitter 22 in direct contact with each other, thereby separating the cathode electrode into a main electrode and an island-type isolating electrode, and disposing an electron emitter on the isolating electrode. Since the line width of the cathode electrode 14 can be secured wider than the so-called island structure that connects the resistor to the resistor, the line resistance of the cathode electrode 14 can be lowered.

Moreover, the above advantages are more advantageously applied as the electron emission display device becomes more precise.

In addition, as described above, the resistive layer 20 according to the present embodiment changes the width W of the portion disposed between the cathode electrode 14 and the electron emitting portion 22, and thus the electron emitting portion 22. It is possible to easily adjust the resistance value corresponding to.

On the other hand, in the manufacturing step of the electron emission display device according to an embodiment of the present invention, the electron emitting portion 22 is a so-called backside exposure to cure the electron emitting portion forming material by irradiating ultraviolet rays from the lower portion of the first substrate 10 It is formed through the law. In general, when the electron emission part is formed by using the backside exposure method, the cathode electrode is formed as a transparent conductive material such as indium tin oxide (ITO). There is a problem to drop.

However, in the present embodiment, as the electron emission part 22 is formed in direct contact with the first substrate 10, the cathode electrode 14 is formed by using a metal other than a conductive material made of a transparent material such as ITO. It is possible to form the electron emission portion through the exposure method.

Therefore, the electron emission display device of the present embodiment can improve the resistance characteristics of the cathode electrode 14 by using the cathode electrode 14 as a metal.

Of course, in the present invention, the case where the cathode electrode 14 is formed of a transparent conductive material such as ITO is not excluded.

The electron emission section 22 is made of materials that emit electrons when an electric field is applied in a vacuum, such as a carbon-based material or a nanometer (nm) size material. That is, the electron emission portion 22 is composed of carbon nanotubes, graphite, graphite nanofibers, diamond, carbon on diamond, fullerene (C ₆₀ ), silicon nanowires, and combinations thereof. On the other hand, the electron emission portion 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 respective 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 formed on the first substrate 10. To be exposed. 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 second insulating layer 24 and the focusing electrode 26 are sequentially formed on the gate electrodes 18. A second insulating layer 24 is positioned below the focusing electrode 26 to insulate the gate electrodes 18 and the focusing electrode 26, and passes the electron beam through the second insulating layer 24 and the focusing electrode 26. Openings 241 and 261 are provided.

The focusing electrode 26 forms an opening corresponding to each of the electron emission units 22 to individually focus electrons emitted from each electron emission unit 22, or one unit pixel by forming an opening for each unit pixel. The electrons emitted by can be collectively focused. The second case is shown in the figure.

On one surface of the second substrate 12 opposite to the first substrate 10, a fluorescent layer 28, for example, red, green, and blue fluorescent layers 28R, 28G, and 28B may be disposed at random intervals. The black layer 30 is formed between the fluorescent layers 28R, 28G, and 28B to improve contrast of the screen. The fluorescent layers 28R, 28G, and 28B are 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.

Meanwhile, the anode electrode 32 may be formed of a transparent conductive film such as ITO, in which case the anode electrode 32 is positioned on one surface of the fluorescent layer 28 and the black layer 30 facing the second substrate 12. do. Moreover, the structure which further forms a metal film using the above-mentioned transparent conductive film as the anode electrode 32 is also possible.

In addition, spacers 34 are disposed between the first substrate 10 and the second substrate 12 to maintain a constant distance between the two substrates 10 and 12 against the compressive force applied to the vacuum container. The spacers 34 are positioned to correspond to the black layer 30 so as not to invade the fluorescent layer 28.

Next, the driving process of the above-mentioned electron emission display device will be described.

The electron emission display device is driven by supplying a predetermined voltage from outside to the cathode electrodes 14, the gate electrodes 18, the focusing electrode 26, and the anode electrode 32.

For example, any one of the cathode electrodes 14 and the gate electrodes 18 serves as scan electrodes by receiving a scan driving voltage, and the other electrodes serve as data electrodes by receiving a data driving voltage. .

The focusing electrode 26 receives a voltage required for electron beam focusing, for example, a negative DC voltage of 0 volts (V) or several to several tens of volts (V), and the anode electrode 32 is a voltage required for electron beam acceleration. A positive DC voltage of several hundred to thousands of volts (V) 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 the threshold, thereby emitting electrons from the electron emission unit 22. The emitted electrons are focused through the opening 261 of the focusing electrode 26 to the center of the electron beam bundle, 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 to implement an arbitrary image.

In the above driving process, the electron emission display device of this embodiment can adjust the individual resistance to the electron emission portion 22 through the resistive layer 20, thereby accurately controlling the emission current for each electron emission portion 22 Since the light emission uniformity for each unit pixel can be improved more effectively.

Meanwhile, in the present embodiment, only the structure in which the cathode electrode is formed on the substrate and the resistance layer is sequentially disposed on the cathode electrode is described and illustrated, but the present invention is not limited thereto. For example, the stacking order of the cathode electrode and the resistive layer may be modified if the electron emission part maintains a pattern that may be disposed in direct contact with the substrate. However, in the case of the above-described embodiment in terms of manufacturing, it may have an advantageous side.

In the above description of the preferred embodiment of the present invention, 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 present invention can provide a resistive layer while reducing the loss area of the cathode electrode as much as possible for one electron emission portion, thereby reducing the line resistance for the cathode electrode. In addition, it is possible to optimize the adjustment of the resistance value for each electron emitter to make the degree of electron emission emitted from each electron emitter uniform, thereby improving luminance uniformity between pixels, thereby realizing a good image.

Securing the electron emission uniformity can prevent excessive emission of electrons at any part of the electron emission part in the entire electron emission part, thereby improving the life characteristics of the electron emission device and the electron emission display device having the same. You can expect

Furthermore, the electron emission display device of the present invention can minimize the loss area caused by the resistive layer in one cathode electrode, so that the pitch thereof can be made small when patterning a plurality of cathode electrodes connected to the resistive layer on the substrate. have.

Therefore, the electron emission display device of the present invention is easy to implement high definition.

Claims (13)

Board; A cathode electrode having a first opening and formed on the substrate; A resistance layer formed on the substrate with a second opening corresponding to the first opening and covering the cathode electrode; And And an electron emission unit disposed in the first opening and the second opening and electrically connected to the resistance layer. The method of claim 1, And said electron emitting portion is in direct contact with said substrate. The method of claim 1, And the first and second openings are formed in a circular shape. The method of claim 3, wherein And said first opening and said second opening are formed concentrically. The method according to claim 3 or 4, And the diameter of the second opening is smaller than the diameter of the first opening. The method of claim 1, And the cathode electrode is formed of a metal. The method of claim 1, And the resistive layer is formed of amorphous silicon. The method of claim 1, And the cathode electrode has a stripe pattern formed along one direction of the substrate, and the resistive layer has a pattern corresponding to the pattern of the cathode electrode formed along the cathode electrode. The method of claim 1, An electron emitting device in direct contact with said electron emitting portion with said resistive layer disposed within said first opening. The method of claim 1, And the electron emission unit is at least one selected from the group consisting of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond phase carbons, fullerenes (C ₆₀ ), and silicon nanowires. The method of claim 1, And a gate electrode and a focusing electrode formed on said cathode electrode, wherein said cathode electrode, said gate electrode and said focusing electrode are insulated from each other. An electron emitting device according to any one of claims 1 to 7; Another substrate disposed opposite the substrate; And And a light emitting unit provided on one surface of the other substrate. The method of claim 12, The light emitting unit, A fluorescent layer formed on the other substrate; And And an anode electrode formed on the other substrate while being connected to the fluorescent layer.

Images