KR20070046516A - Electron emission device and electron emission display device using the same - Google Patents

Abstract

The electron emission display device according to the present invention is electrically connected to and disposed on a substrate, cathode electrodes formed on the substrate, an insulating layer formed on the substrate while covering the cathode electrodes, gate electrodes formed on the insulating layer, and cathode electrodes. An insulating layer comprising electron emitting portions, the insulating layer having a first opening formed so that the electron emitting portion is disposed, formed over the first insulating portion and the first insulating portion covering the cathode electrodes, and having a diameter larger than the first opening; And a second insulating portion having two openings, wherein the electron emission portion is disposed inside the first opening.

Electron emission, insulating layer, cathode, gate electrode, opening, insulating layer

Description

ELECTRON EMISSION DEVICE AND ELECTRON EMISSION DISPLAY DEVICE USING THE SAME

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

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

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

4A-4H are schematic diagrams at each step shown to illustrate a method of manufacturing an electron emitting device according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron emission device, and more particularly, to an electron emission device including an electron emission unit controlled by a driving voltage of a cathode electrode and a gate electrode and an electron emission display device using the same.

Electron emitting devices are devices that are used as light sources in equipment that requires a focused electron beam, such as electron emission display devices, electron beam lithography equipment or scanning tunneling microscopy.

Such an electron emission device includes a plurality of electron emission devices, and generally, an electron emission element is a method using a hot cathode and a cold cathode according to the type of electron source. Can be classified.

Here, the electron-emitting device using the cold cathode is a field emitter array (FEA) type, a surface conduction emission type (SCE) type, a metal-insulation layer-metal Metal (MIM) type and Metal-Insulator-Semiconductor (MIS) type are known.

Among them, the FEA type electron emission device includes an electron emission unit and driving electrodes for controlling electron emission of the electron emission unit, and includes one cathode electrode and one gate electrode, and has a low work function as a material of the electron emission unit. Or a high aspect ratio material, such as molybdenum (Mo) or silicon (Si), with a sharp tip structure, or an electric field in vacuum using carbon-based materials such as carbon nanotubes and graphite and diamond-like carbon. By using the principle that the electron is easily emitted by.

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.

That is, the conventional electron emitting device includes a plurality of driving electrodes that function as scan electrodes and data electrodes in addition to the electron emitting part, so that the electron emission amount and the electron emission amount per pixel are controlled by the action of the electron emitting part and the driving electrodes. To control. The electron emission display device excites the fluorescent layer with the electrons emitted from the electron emission unit to perform a predetermined light emission or display function.

The electron emission unit may be formed of various materials, and various methods for forming the electron emission unit have been proposed. Among these methods, the method of forming an electron emitting portion by pasting an electron emitting material has an advantage that the process is very simple.

However, when the electron emission material is pasted to form the electron emission portion, the shape thereof becomes uneven, and therefore, there is a problem that the emission current emitted from the electron emission portion also becomes nonuniform.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an electron emission device and an electron emission display device using the same that can uniformly form the electron emission portion to obtain a uniform emission current.

In order to achieve the above object, the electron emission display device according to the present invention is a substrate, cathode electrodes formed on the substrate, an insulating layer formed on the substrate covering the cathode electrodes, gate electrodes formed on the insulating layer and the cathode electrode And electron emission portions disposed in electrical connection with each other, the insulating layer having a first opening formed to arrange the electron emission portion, and formed on the first insulation portion and the first insulation portion covering the cathode electrodes, And a second insulating portion having a second opening having a diameter larger than the first opening, wherein the electron emission portion is disposed inside the first opening.

In addition, the electron emission unit may be formed to correspond to the shape and size of the first opening.

In addition, the first insulating portion and the second insulating portion may be formed of different materials.

In addition, the second insulating part may be made of a material having a higher etching rate than the first insulating part.

The display device may further include a focusing electrode that is insulated from the gate electrodes and positioned above the gate electrodes.

In addition, the electron emission unit may include at least one material selected from the group consisting of carbon nanotubes, graphite, graphite nanofibers, diamond, diamond-like carbon, fullerene (C ₆₀ ), and silicon nanowires.

In addition, the electron emission display device according to the present invention is formed on the first substrate and the second substrate disposed opposite to each other, the cathode electrodes formed on the first substrate, the insulating layer formed on the substrate covering the cathode electrodes, the insulating layer A gate electrode, electron emission parts electrically connected to and disposed on the cathode electrodes, fluorescent layers formed on one surface of the second substrate, and an anode electrode positioned on one surface of the fluorescent layers, and the insulating layer includes the electron emission parts And a second insulating portion having a first opening formed so as to be formed on the first insulating portion and covering the cathode electrodes, and having a second opening having a larger diameter than the first opening.

Further, a method of manufacturing an electron emitting device according to an embodiment of the present invention comprises the steps of forming a cathode electrode on a substrate, forming a first insulating portion covering the cathode electrode on the substrate, exposing the cathode electrode to the first insulating portion Forming an opening, forming a second insulating portion over the first insulating portion, forming a conductive film over the second insulating portion, and exposing the first opening on the substrate to the conductive film and the second insulating portion, respectively. Forming an opening of the substrate, forming a gate electrode by patterning the conductive film, forming an electron emission material inside the first opening, and removing the portion formed over the first insulation of the electron emission material to form the electron emission unit It includes a step.

In addition, forming the electron emission material may include forming a sacrificial layer over the gate electrode and the second insulating layer, forming a sacrificial layer opening having a diameter larger than the first opening in the sacrificial layer, and forming an electron in the sacrificial layer opening. Applying the emitter forming material, exposing and developing the electron emitting forming material and patterning the same, and removing the sacrificial layer.

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 emitting device according to an embodiment of the present invention, and FIG. 2 is a partial cross-sectional view of the electron emitting device shown in FIG.

As shown in FIG. 1, the present invention provides an electron emitting device in which electron emitting elements are arranged in an array on a substrate 2.

More specifically, the cathode electrodes 4 are formed on the substrate 2 in a stripe pattern along one direction (y-axis direction of the drawing) of the substrate 2 and the insulating layer 6 covering the cathode electrodes 4. ) Is formed throughout the substrate 2. On the insulating layer 6, the gate electrodes 8 are formed in a stripe pattern along a direction orthogonal to the cathode electrode 4 (x-axis direction in the drawing).

The insulating layer 6 is in direct contact with the cathode electrode 4 and substantially covers the cathode electrode 4, and the second insulating portion 62 positioned above the first insulating portion 61. ) The first insulation portion 61 and the second insulation portion 62 are divided by dotted lines in FIG. 2.

A plurality of first openings 612 are formed in the first insulating portion 61 at each intersection of the cathode electrode 4 and the gate electrode 8, and the first openings 612 are formed in the second insulating portion 62. The second opening 622 is formed to correspond to.

In addition, a gate opening 81 corresponding to the second opening 622 formed in the second insulating part 62 is formed in the gate electrode 8.

In addition, the electron emission part 10 is formed in the first insulating part 61 positioned in the second opening 622 while filling the first opening 612.

As described above, in the electron emission device according to the exemplary embodiment of the present invention, the electron emission unit 10 is disposed in the first opening 612 to correspond to its shape and size so that the electron emission units 10 are uniform with each other. Have a diameter and height.

In the drawing, the electron emission parts 10 are formed in a circular shape and are arranged in a line along the length direction of the cathode electrode 4. However, the planar shape of the electron emission unit 10, the number and arrangement form per pixel area, etc. are not limited to the illustrated example.

In addition, the electron emission unit 10 may be formed of materials emitting electrons when an electric field is applied in a vacuum, for example, a carbon-based material or a nanometer (nm) size material. Preferred materials for use as the electron emitter 10 include carbon nanotubes, graphite, graphite nanofibers, diamond, diamond-like carbon, fullerene (C ₆₀ ), silicon nanowires, and combinations thereof.

In addition, the electron emission device according to the exemplary embodiment of the present invention may include another insulating layer 14 and a focusing electrode 16 on the insulating layer 6 and the gate electrode 8. In another insulating layer 14 and the focusing electrode 16, for example, openings 142 and 162 corresponding to the crossing regions are formed, respectively. The focusing electrode 16 may be formed to be positioned on the whole of another insulating layer 14, as shown in FIG. 1.

So far, the electron emitting device has been described, and the electron emitting device can be applied to an electron emitting display device that emits light and displays.

3 is a partial cross-sectional view of an electron emission display device using an electron emission device according to an embodiment of the present invention. Hereinafter, in the electron emission display device according to the embodiment of the present invention, the same components as the electron emission device use the same reference numerals for convenience, and the substrate of the electron emission device is referred to as a first substrate.

As shown in FIG. 3, the electron emission display device according to the exemplary embodiment of the present invention includes a first substrate 2 and a second substrate 18 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 2 and the second substrate to bond the two substrates, and the internal space is evacuated to a vacuum so that the first substrate 2, the second substrate 18, and The sealing member constitutes a vacuum container.

The second substrate 18 is provided with a light emitting unit that emits light by electrons emitted from the electron emission unit 10.

More specifically, the red (R), green (G), and blue (B) fluorescent layers 20 may have a predetermined distance from each other on one surface of the second substrate 18 opposite to the first substrate 2. The black layer 22 is formed between the fluorescent layers 20 to improve contrast of the screen. The red (R), green (G), and blue (B) fluorescent layers 20 may be formed separately for each subpixel, but may also be formed in a stripe pattern.

An anode electrode 24 made of a metal film such as aluminum is formed on the fluorescent layer 20 and the black layer 22. The anode electrode 24 receives an anode voltage required for electron beam acceleration from the outside, and reflects the visible light emitted toward the first substrate 2 of the visible light emitted from the fluorescent layer 20 toward the second substrate 18. It serves to increase the luminance of.

On the other hand, the anode electrode may be made of a transparent conductive film such as indium tin oxide (ITO) rather than a metal film. In this case, the anode electrode may be positioned on one surface of the fluorescent layer facing the second substrate and the black layer, and may be formed in plural in a predetermined pattern. In addition, the anode electrode may have a structure in which the above-mentioned transparent conductive film and a metal film are simultaneously formed.

In addition, a plurality of spacers 26 are provided between the first substrate 2 and the second substrate 18 to support the compressive force applied to the vacuum vessel, and to support the first substrate 2 and the second substrate 18. Keep the interval constant. The spacers 26 are disposed corresponding to the non-light emitting region where the black layer 24 is located so as not to invade the fluorescent layer 20.

The electron emission display device having the above-described configuration is driven while receiving a predetermined voltage from the outside on the cathode electrode 4, the gate electrode 8, the focusing electrode 16, and the anode electrode 24. For example, any one of the cathode electrode 4 and the gate electrode 8 receives a scan driving voltage to function as a scan electrode, and the other electrode receives a data driving voltage to function as a data electrode. In addition, the focusing electrode 16 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 24 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 unit 10 in the pixels in which the voltage difference between the cathode electrode 4 and the gate electrode 8 is greater than or equal to the threshold, and electrons are emitted therefrom. The emitted electrons are focused through the opening 162 of the focusing electrode 16 to the center of the electron beam bundle, and are attracted by the high voltage applied to the anode electrode 24 to impinge on the fluorescent layer 20 of the corresponding pixel to emit light. Let's do it.

4A to 4H are schematic views at each step shown to explain a method of manufacturing an electron emitting device according to an exemplary embodiment of the present invention, and a method of manufacturing the electron emitting device will be described with reference to the drawings. Illustration of the focusing electrode is omitted in this embodiment.

First, as shown in FIG. 4A, a conductive film, for example, transparent ITO, is coated on the substrate 2 and patterned into a stripe shape to form the cathode electrode 4. Thereafter, the first insulating material is printed on the entire substrate 2, and then dried and baked to form the first insulating portion 61.

Next, as illustrated in FIG. 4B, a plurality of first openings 612 are formed in the first insulating portion 61 by using a mask layer (not shown).

Next, as shown in FIG. 4C, after forming a second insulating portion 62 by printing a second insulating material on the first insulating portion 61, the conductive film is formed on the second insulating portion 62 again. (8a) is coated. In this case, as the second insulating material, an etching rate higher than that of the first insulating material is used.

The first insulating material and the second insulating material may be made of separate materials having different compositions, or the etching rate may be adjusted by changing the composition ratio of the same composition. For example, both the first insulating material and the second insulating material may be made of a material containing PbO and SiO ₂ as main components, and TiO ₂ , B ₂ O ₃ , and the like, wherein the ratio of B ₂ O ₃ is adjusted. Etch rate can be adjusted.

Next, as shown in FIG. 4D, the gate opening 81 is formed in the conductive film 8a formed on the second insulating portion 62 by using a mask layer (not shown). Then, the second insulating portion 62 exposed by the gate opening 81 formed in the conductive film 8a by immersing the substrate 2 in the etching solution is etched to form another second opening in the second insulating portion 62. After forming 622, the conductive film 8a is patterned to form the gate electrode 8.

At this time, when the second insulation 62 is etched, the first insulation 61 is not etched and must maintain its shape. The reason why the second insulating material has a higher etching rate than that of the first insulating material is for the same reason as described above.

On the other hand, the insulating layer 6 of such a shape can be formed using two masks, unlike the above-mentioned. That is, the insulating layer 6 is formed on the pattern of the cathode electrode 4, the gate electrode 8 is formed using a first mask corresponding to the shape of the second opening 622, and half-etched. The second openings 622 are sequentially formed through etching.

Next, the first opening 612 may be etched to the upper portion of the cathode electrode 4 using the second mask to form an insulating layer as shown in FIG. 4D. In this case, the insulating layer 6 may be formed of a single material.

Next, as shown in FIG. 4E, the sacrificial layer 28 is applied to the entire substrate 2, and the sacrificial layer has a size larger than the diameter of the first opening 612 and smaller than the diameter of the second opening 622. The opening 282 is formed.

The sacrificial layer 28 is intended to prevent the electron-emitting material to be applied from remaining on the gate electrode 8 and the insulating layer 6 and affecting the properties of the electron-emitting device. It may be formed of a material such as metal.

Next, as shown in FIG. 4F, a paste-like mixture 30 containing an electron emitting material and a photosensitive material is applied to the entire structure provided on the substrate 2. In this case, the mixture 30 may be filled in the first opening 612. Then, ultraviolet rays (shown by arrows) are irradiated from the rear surface of the substrate 2 in a state where the exposure mask 32 is disposed on the rear surface of the substrate 2 to selectively cure a mixture of specific sites.

Next, as shown in FIG. 4G, the uncured mixture is removed through development, the sacrificial layer is removed, and the remaining mixture 28 is dried and calcined.

Finally, as shown in FIG. 4H, as an example of mechanical post-treatment, the mixture formed on the first insulating portion 61 is removed by taping to emit electrons having a uniform diameter and height into the first opening 612. Allow portion 10 to be formed.

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 device according to the embodiment of the present invention has the effect of uniformly forming the diameter and height of the electron emission unit to improve the uniformity of the emission current in the electron emission unit.

Claims (14)

Board; Cathode electrodes formed on the substrate; An insulating layer formed on the substrate while covering the cathode electrodes; Gate electrodes formed on the insulating layer; And Electron emission parts disposed in electrical connection with the cathode electrodes; Including, The insulating layer, A first insulating part having a first opening formed to arrange the electron emission part and covering the cathode electrodes; And A second insulating part formed on the first insulating part, the second insulating part having a second opening having a larger diameter than the first opening part; And the electron emitting portion is disposed inside the first opening. According to claim 1, The electron emitting device is formed to correspond to the shape and size of the first opening. According to claim 1, And the first insulating portion and the second insulating portion are formed of different materials. The method of claim 3, wherein And the second insulating portion is made of a material having a higher etching rate than the first insulating portion. The method of claim 1, And a focusing electrode positioned over the gate electrodes and insulated from the gate electrodes. According to 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. A first substrate and a second substrate disposed to face each other; Cathode electrodes formed on the first substrate; An insulating layer formed on the substrate while covering the cathode electrodes; Gate electrodes formed on the insulating layer; Electron emission parts electrically connected to and disposed on the cathode electrodes; Fluorescent layers formed on one surface of the second substrate; And An anode located on one surface of the fluorescent layers Including, The insulating layer, A first insulating part having a first opening formed to arrange the electron emission part and covering the cathode electrodes; And A second insulating part formed on the first insulating part, the second insulating part having a second opening having a larger diameter than the first opening part; And the electron emission unit is disposed inside the first opening. The method of claim 7, wherein And the electron emission unit is formed to correspond to the shape and size of the first opening. Forming a cathode electrode over the substrate; An insulating layer including a first insulating portion having a first opening portion over the cathode and a second insulating portion having a second opening having a diameter larger than the first opening portion and a gate electrode formed over the insulating layer Forming a; Forming an electron emission material in the first opening; And Removing the portion of the electron-emitting material formed over the first insulator to form an electron-emitting portion Method of manufacturing an electron emitting device comprising a. The method of claim 9, Forming the insulating layer and the gate electrode, Forming a first insulating portion covering the cathode electrode on the substrate; Forming a first opening exposing the cathode electrode to the first insulating portion; Forming a second insulation portion over the first insulation portion; Forming a conductive film on the second insulating portion; Forming respective openings to expose the first openings on the substrate in the conductive film and the second insulating portion; And Patterning the conductive layer to form a gate electrode Method of manufacturing an electron emitting device comprising a. The method of claim 10, And the first insulating portion and the second insulating portion are formed of different materials. The method of claim 11, wherein And the second insulating portion is made of a material having an etching rate higher than that of the first insulating portion. The method of claim 9, Forming the insulating layer and the gate electrode, Forming an insulating layer covering the cathode electrode on the substrate; Forming a conductive film on the insulating layer; Patterning the conductive film to form a gate electrode; Half etching the insulating layer to form a second opening; And Forming a first opening in the second opening to expose the cathode electrode Method of manufacturing an electron emitting device comprising a. The method of claim 9, Forming the electron emitting material may include Forming a sacrificial layer over the gate electrode and the second insulating layer; Forming a sacrificial layer opening in the sacrificial layer having a diameter larger than the first opening; Applying an electron emission forming material to the sacrificial layer opening; Exposing and developing the electron emission forming material to be patterned; And Removing the sacrificial layer Method of manufacturing an electron emitting device comprising a.

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