KR20070014624A - Electron emission device and method of manufacturing the same - Google Patents

Abstract

An electron emission device and a method for manufacturing the same are provided to form a plurality of fine holes on a gate electrode by using a bubble generation layer instead of forming an additional grid electrode or an additional focusing electrode. A cathode electrode(6) is formed on a substrate(2). An insulating layer(8) is formed on an entire surface of the substrate in order to cover the cathode electrode. An opening(8a) is formed on the insulating layer in order to expose a part of the cathode electrode. An electron emission unit(12) is formed on the exposed part of the cathode electrode. A bubble generation layer is formed on the cathode electrode and the electron emission unit. A gate electrode(10) is formed on the insulating layer and the bubble generation layer. A plurality of fine holes(10a) are formed on the gate electrode by baking the bubble generation layer. The bubble generation layer is removed therefrom.

Description

ELECTRON EMISSION DEVICE AND METHOD OF MANUFACTURING THE SAME

1A to 1F are sequential process cross-sectional views illustrating a method of manufacturing an electron emission device according to an exemplary embodiment of the present invention.

2 is a partially exploded perspective view of an electron emission device according to an exemplary embodiment of the present invention.

3 is a partial cross-sectional view of 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 emitting device, and more particularly, to an electron emitting device having an improved shape of a gate electrode in order to increase emission efficiency and suppress electron beam spreading, and a method of manufacturing the same.

In general, electron emission devices include a method of using a hot cathode and a cold cathode as an electron source.

Here, the electron-emitting device using a cold cathode is a field emitter array (FEA) type, surface conduction emission (SCE) type, metal-insulator-metal-insulator- metal (MIM) type and metal-insulator-semiconductor (MIS) type and the like are known.

Among these, the FEA type electron emitting device uses a principle that electrons are easily emitted by an electric field during vacuum when a material having a low work function or a large aspect ratio is used as the electron source. Molybdenum (Mo) Alternatively, an example is described in which an electron emission portion is formed by a spint type having a sharp tip of silicon (Si) or the like, or an electron emission portion is formed of carbon-based materials such as carbon nanotubes and graphite and diamond-like carbon. have.

A conventional FEA type electron emission device has a cathode electrode and a gate electrode as driving electrodes for driving an electron emission portion together with an electron emission portion on a first substrate of two substrates constituting a vacuum container, and a fluorescent layer on a second substrate. An anode electrode is provided to allow electrons emitted from the first substrate side to be efficiently accelerated toward the fluorescent layer to perform a predetermined light emission or display function.

Since the spin type electron emitter proposed at the beginning has an excellent degree of integration in each pixel area, there is an advantage of excellent electron emission uniformity and emission uniformity for each pixel. However, since the spin type electron emitting part is manufactured by a known semiconductor process, the process is complicated, and there is a disadvantage that it is not suitable for manufacturing a large area device.

As a result, recently, a technique of forming an electron emission part by applying a carbon-based material on a cathode electrode by a so-called thick film process such as screen printing has been developed. In this case, the insulating layer positioned between the cathode electrode and the gate electrode is also generally formed by a thick film process such as screen printing, and an opening is formed in the insulating layer through wet etching to provide a space in which the electron emission part is to be located.

Compared to the semiconductor process, the technology is easier to manufacture and has advantages in manufacturing a large area device. However, since the degree of integration of the electron emitter is lower than that of the spin type, the number of electron emitters having a larger area than the spin type in each pixel area is reduced. Prepared.

In such a structure, the distance between the electron emitting part and the gate electrode is increased, so that the electric field is concentrated at the edge of the electron emitting part having the closest distance to the gate electrode, rather than the electric field concentrated on the entire electron emitting part when the electron emitting element is operated. Emissions tend to occur. As a result, the emission efficiency is lowered and significant beam spreading occurs, which requires a separate focusing structure for suppressing the emission efficiency.

In addition, in the structure, since the entire electron emission part is positioned to face the anode electrode, the anode electric field directly affects the electron emission part. As a result, an emission failure may occur, for example, electrons are emitted from the electron emission portion of the pixel to be turned off due to the anode electric field.

Accordingly, an object of the present invention is to solve the above problems, and an object of the present invention is to increase emission efficiency, minimize beam spread, and effectively block an influence of an anode field on an electron emission part, and It is to provide a manufacturing method.

In order to achieve the above object, the present invention provides a method of forming a cathode on a substrate, forming an insulating layer on the entire surface of the substrate to cover the cathode, and exposing a portion of the surface of the cathode on the insulating layer. Forming an opening, forming an electron emitting portion over the exposed cathode electrode, forming a bubble generating layer over the cathode electrode and the electron emitting portion to fill only the opening, and forming a gate electrode over the insulating layer and the bubble generating layer. And forming a plurality of micro holes in the gate electrode by firing the bubble generating layer and simultaneously removing the bubble generating layer.

Here, the bubble generating layer may include an azodicarbonamide system as the bubble generating agent, and the bubble generating layer may further include a photosensitive material.

In addition, the firing of the bubble generating layer can be carried out at a temperature of 300 to 600 ℃.

In addition, the gate electrode may be formed of a conductive material containing silver (Ag) or a bubble generator on a paste.

In addition, the micro holes of the gate electrode may have a size of about 2 μm or less.

In addition, the forming of the electron emission unit may include a process of screen printing, drying, and firing a carbon-based material or a nanometer size material, and may further include an activation process of tearing off a part of the surface of the electron emission unit.

In order to achieve the above object, the present invention, the first substrate and the second substrate disposed to face each other, the cathode electrodes formed on the first substrate, the electron emitting portions formed on the cathode electrode, and the first substrate An insulating layer having an opening for exposing the electron emission portion, a gate electrode forming a plurality of micro holes formed on the insulating layer and randomly arranged over the opening while covering the opening, a fluorescent layer formed on the second substrate, And an anode electrode formed on one surface of the fluorescent layer, wherein the micro holes of the gate electrode have an size of 2 μm or less.

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

First, a method of manufacturing an electron emission device according to an exemplary embodiment of the present invention will be described with reference to FIGS. 1A to 1F.

1A to 1F are sequential process cross-sectional views illustrating a method of manufacturing an electron emission device according to an exemplary embodiment of the present invention.

Referring to FIG. 1A, the cathode electrode 6 is formed on the first substrate 2 in a stripe pattern along one direction, and the insulating layer is formed on the entire surface of the first substrate 2 while covering the cathode electrode 6. 8) form. The insulating layer 8 may be formed to a thickness of approximately 5 to 30 μm by repeating the screen printing, drying and baking processes several times.

Next, the insulating layer 8 is patterned by a photolithography process and an etching process to form an opening 8a exposing a part of the surface of the cathode electrode 6. This opening 8a is located at the intersection of the cathode electrode 6 and the gate electrode to be formed later.

Referring to FIG. 1B, a thick film or thin film electron emission part 12 is formed on the exposed cathode electrode 6. The electron emission unit 12 is made of materials that emit electrons when an electric field is applied, such as carbon-based materials or nanometer-sized materials, and includes carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, and silicon nanowires. And the like can be used as the electron emitting material.

First, the thick film type electron emission unit 12 mixes an organic material such as a vehicle and a binder with a powdered electron emission material to form a paste-like electron emission material having a suitable viscosity by printing, and then onto the exposed cathode electrode 6. This electron-emitting material can be formed by screen printing, drying and baking.

On the other hand, the thick film type electron emission unit 12 further includes a photosensitive material in the above-mentioned electron-emitting material on the paste, and ② screen-prints the electron-emitting material on the entire surface of the first substrate 2, (3) In the state in which an exposure mask (not shown) is disposed on the rear surface of the first substrate 2, ultraviolet rays are irradiated through the rear surface of the first substrate 2 to selectively cure the electron-emitting material in the specific region of the cathode electrode 6. And e) removing the uncured electron-emitting material through development, followed by drying and firing.

In this case, the first substrate 2 is made of a transparent substrate, and the cathode electrode 6 is made of a transparent conductive material such as indium tin oxide (ITO). In the above method using exposure and development, the curing of the electron-emitting material occurs from the surface of the cathode electrode 6 so that the adhesion of the electron-emitting portion 12 to the cathode electrode 6 is excellent, and the cathode electrode 6 and There is an advantage that the contact resistance between the electron emitting portions 12 is low.

On the other hand, in the thick film-type electron emitter 12 formed as described above, most of the electron-emitting materials are buried in the organic material does not contribute to the electron emission. As a result, a physical activation method of removing a portion of the surface of the electron emission part 12 by attaching and detaching an adhesive tape (not shown) on the electron emission part 12 is carried out so that a larger amount is applied to the surface of the electron emission part 12. The electron emitting portion 12 of the can be exposed.

The thin film electron emission part 12 may be formed by chemical vapor deposition, sputtering, or direct growth.

Referring to FIG. 1C, a bubble generating layer 30 is formed on the cathode electrode 6 and the electron emission part 12 to fill only the opening 8a.

The bubble generating layer 30 may contain a bubble generating agent that generates bubbles at a predetermined temperature, for example, an azodicarbonamide system.

In addition, the bubble generating layer 30 may further include a photosensitive material. Then, the bubble generating layer 30 can remain only in the opening 8a by applying and exposing and developing the mixture containing the bubble generating agent and the photosensitive material.

Referring to FIG. 1D, gate electrodes 10 disposed in a scribe pattern are formed on the insulating layer 8 and the bubble generating layer 30 in a direction orthogonal to the cathode electrode 6. The gate electrode 10 may be formed by a screen printing method using silver (Ag) on a paste having a viscosity suitable for printing.

Referring to FIG. 1E, the bubble generating layer 30 is fired at a temperature of 300 to 600 ° C. Then, the bubble generating layer 30 is burned and removed while generating bubbles, and at this time, bubbles are sublimed while passing through the gate electrode 10 to form a plurality of microholes in the gate electrode 10 as illustrated in FIG. 1F. 10a) is randomly formed. At this time, the micro holes 10a may have a size of about 2 μm or less, more specifically about 1 to 2 μm.

Meanwhile, in the above embodiment, silver (Ag) in the paste is used as the gate electrode material, but the azodicarbon is formed so that the micro holes 10a are more easily formed in the gate electrode 10 when the bubble generating layer 30 is fired. Conductive materials such as silver (Ag) on pastes containing bubble generators such as amides (azodicarbonmide) can be used.

As such, the method of manufacturing the electron emission device according to the present embodiment forms a plurality of fine holes 10a in the gate electrode 10 instead of installing a separate grid electrode or focusing electrode for electron beam focusing. It can simplify and ensure the ease of processing.

In addition, since the plurality of micro holes 10a provided in the gate electrode 10 are formed by firing by applying the bubble generating layer 30, there is no need to perform a separate photolithography process, an etching process, etc. Can reduce the cost.

2 and 3 are partially exploded perspective and partial cross-sectional views of the electron emission device according to the embodiment of the present invention, respectively.

Referring to the drawings, in the electron-emitting device, the first substrate 2 and the second substrate 4 constituting the vacuum container are disposed to face each other in parallel at predetermined intervals. On an opposing surface of the first substrate 2 with the second substrate 4, an electron emission unit for emitting electrons toward the second substrate 4 is provided, and the first substrate 2 of the second substrate 4 is provided. On the opposite surface to the light emitting unit, a light emitting unit is provided that emits visible light by the electrons to cause any light emission or display.

In more detail, the cathode electrodes 6 are formed on the first substrate 2 in a stripe pattern along one direction (y-axis direction in the drawing), and cover the cathode electrodes 6 while covering the first substrate ( 2) The insulating layer 8 is formed in the whole. Gate electrodes 10 are formed on the insulating layer 8 in a stripe pattern along a direction orthogonal to the cathode electrode 6 (x-axis direction in the drawing).

In this embodiment, when the region where the cathode electrode 6 and the gate electrode 10 cross each other is defined as a pixel region, at least one opening 8a is formed in each pixel region in the insulating layer 8 so that the cathode electrode ( Expose some surface of 6).

The electron emission part 12 is formed on the cathode electrode 6 in the opening 8a, and a plurality of micro holes 10a are randomly formed in the gate electrode 10 corresponding to the opening 8a. The electron emission part 12 is partially exposed.

The electron emission unit 12 is formed of materials that emit electrons when an electric field is applied, such as a carbon-based material or a nanometer-sized material. The electron emission unit 12 may be made of any one of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, C ₆₀ , silicon nanowires, or a combination thereof, and may be screen printed, directly As the growth, screen printing, direct growth, chemical vapor deposition or sputtering may be applied.

In the drawing, one electron emission part 12 is disposed in each pixel area, and the opening 8a of the insulating layer 8 is rectangular, but the number of the electron emission parts 12 and the insulating layer 8 The shape of the opening 8a is not limited to this and can be variously modified.

The micro holes 10a of the gate 10 block the path of propagation and propagation of electrons emitted from the electron emission unit 12 during operation of the electron emission element, and pass only electrons having a straightness. 2 micrometers or less, More specifically, it has the magnitude | size of about 1-2 micrometers.

Next, a fluorescent layer 16 and a black layer 18 are formed on one surface of the second substrate 4 facing the first substrate 2, and aluminum and the fluorescent layer 16 and the black layer 18 are formed on the surface of the second substrate 4. An anode electrode 20 made of the same metal film is formed. The anode electrode 20 receives a high voltage necessary for accelerating the electron beam from the outside, and reflects the visible light emitted toward the first substrate 2 of the visible light emitted from the fluorescent layer 16 toward the second substrate 4 side. It serves to increase the luminance of.

Meanwhile, the anode electrode 10 may be formed on one surface of the fluorescent layer 16 and the black layer 18 facing the second substrate 4, and in this case, may transmit visible light emitted from the fluorescent layer 16. So that the anode electrode is made of a transparent conductive layer such as ITO.

On the other hand, both the anode electrode of the transparent material and the metal thin film which raises the luminance by the reflection effect may be formed on the second substrate 4.

The fluorescent layer 16 may be disposed in a one-to-one correspondence with the pixel area set on the first substrate 2 or may be formed in a stripe pattern along the vertical direction (y-axis direction of the drawing) of the screen, and the black layer 18 It may be made of an opaque material such as silver chromium or chromium oxide.

A plurality of spacers 32 are disposed between the first substrate 2 and the second substrate 4 described above to maintain a constant distance between the two substrates 2 and 4. In this case, the spacers 22 are disposed corresponding to the non-light emitting region where the black layer 18 is located.

In the electron emission device configured as described above, a positive voltage of several hundred to several thousand volts is applied to the anode electrode 10, and a scan signal voltage is applied to any one of the cathode electrode 6 and the gate electrode 10. At the same time, the data signal voltage is applied to the other electrode to be driven.

Then, in the pixels where the voltage difference between the cathode electrode 6 and the gate electrode 10 is greater than or equal to the threshold, an electric field is formed around the electron emission part 12 to emit electrons therefrom, and the emitted electrons are emitted from the anode electrode 10. It is attracted by the high voltage applied to the fluorescent layer 16 of the corresponding pixel to emit light.

In the present exemplary embodiment, as the gate electrode 10 having the plurality of micro holes 10a is positioned above the electron emitter 12, the opposing area between the electron emitter 12 and the gate electrode 10 may be maximized. The emission efficiency of the electron emission unit 12 may be maximized. That is, since the electric field is concentrated not only on the edge of the electron emission part 12 but also on the entire upper surface of the electron emission part 12 facing the gate electrode, electrons are emitted from the electron emission part 12. Can be.

In addition, in the present exemplary embodiment, as the fine holes 10a are formed in the gate electrode 10 over the electron emitter 12, the electron holes 12a go straight toward the second substrate 4 among the electrons emitted from the electron emitter 12. The propagation path of the electrons that propagate without having is blocked by the gate electrode 10. On the other hand, only electrons having a straightness toward the second substrate 4 among the electrons emitted from the electron emission part 12 are directed to the second substrate 4 through the micro holes 10a.

As a result, the electron emission device of the present embodiment can accurately emit only the fluorescent layer 16 to emit light by increasing the focusing efficiency of electrons emitted from the electron emission unit 12, thereby improving color reproducibility.

In addition, in the present embodiment, since the gate electrode 10 minimizes the exposed area of the electron emission part 12 toward the anode electrode 20, the influence of the anode electric field on the electron emission part 12 is blocked. Therefore, malfunction due to the anode current can be prevented, and a larger voltage can be applied to the anode electrode 20, effectively contributing to increasing the brightness of the screen.

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 method of manufacturing the electron emission device according to the present invention forms a plurality of fine holes in the gate electrode using the bubble generating layer instead of installing a separate grid electrode or focusing electrode, thereby simplifying the manufacturing process. Not only can it be secured, but manufacturing costs can be reduced.

In addition, the electron emitting device according to the present invention by maximizing the emission efficiency of the electron emitting portion by the above-described configuration, block the beam spreading of the electrons to increase the color reproduction rate, and also block the influence of the anode electric field on the electron emitting portion The effect of enabling the application of a high voltage anode voltage is realized.

Claims (10)

Forming a cathode electrode on the substrate; Forming an insulating layer on the entire surface of the substrate to cover the cathode electrode; Forming an opening in the insulating layer to expose a portion of the surface of the cathode; Forming an electron emitter over the exposed cathode electrode; Forming a bubble generating layer on the cathode electrode and the electron emitting portion to fill only the opening; Forming a gate electrode on the insulating layer and the bubble generating layer; And Firing the bubble generating layer to form a plurality of fine holes in the gate electrode and simultaneously removing the bubble generating layer Method of manufacturing an electron emitting device comprising a. The method of claim 1, A method for producing an electron emission device, wherein the bubble generating layer comprises an azodicarbonamide system as a bubble generating agent. The method of claim 1, Method of manufacturing an electron emitting device wherein the bubble generating layer further comprises a photosensitive material. The method according to any one of claims 1 to 3, Firing of the bubble generating layer is a method of manufacturing an electron emitting device performed at a temperature of 300 to 600 ℃. The method of claim 1, A method for manufacturing an electron emission device, wherein the gate electrode is formed of silver (Ag) on a paste. The method of claim 1, The manufacturing method of the electron emission element which forms the said gate electrode from the electrically-conductive material containing a bubble generating agent. The method of claim 1, The method of claim 1, wherein the fine holes of the gate electrode have a size of about 2 μm or less. The method of claim 1, Forming the electron emission portion, Screen-printing, drying and firing carbon-based materials or nanometer-sized materials, The method of manufacturing an electron emission device further comprises an activation process of removing a part of the surface of the electron emission portion. A first substrate and a second substrate disposed to face each other; Cathode electrodes formed on the first substrate; Electron emission parts formed on the cathode electrode; An insulating layer having an opening for exposing the electron emission portion over the first substrate; A gate electrode formed on the insulating layer and forming a plurality of micro holes randomly arranged over the opening while covering the opening; A fluorescent layer formed on the second substrate; And An anode electrode formed on one surface of the fluorescent layer, The electron emission device of the fine holes of the gate electrode having a size of 2㎛ or less. The method of claim 9, 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.

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