KR20050086236A - Surface treatment method of emitter and manufacturing method of electron emission display device using the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method of an electron emission source and a method of manufacturing an electron emission display device using the same, wherein the electron of a flat panel display device including carbon nanotubes (CNT), glass frit, a binder resin, and a solvent Printing and coating the composition for emitting source forming to produce an electron emitting source; It provides a method of manufacturing an electron emission display device comprising the step of spraying and etching the high pressure compressed CO ₂ aerosol to the electron emission source. The present invention sprays a sublimable gas such as CO ₂ gas in the form of an aerosol to orient the carbon nanotubes in the electric field direction, thereby surface treating the electron emission source, thereby increasing the number of carbon nanotubes contributing to the electron emission, thereby increasing the number of carbon nanotubes. An electron emission display device having remarkably excellent electron emission characteristics can be provided.

Description

Surface treatment method of electron emission source and manufacturing method of electron emission display device using the same {SURFACE TREATMENT METHOD OF EMITTER AND MANUFACTURING METHOD OF ELECTRON EMISSION DISPLAY DEVICE USING THE SAME}

[Industrial use]

The present invention relates to a surface treatment method of an electron emission source and a method of manufacturing an electron emission display device using the same. More specifically, the organic material and carbon on the surface by spraying CO ₂ particles, which are aerosol-type sublimable particles, on the electron emission source The present invention relates to a surface treatment method of an electron emission source and a method of manufacturing an electron emission display device using the same, by which the carbon nanotubes are effectively exposed on the surface by etching the nanotube film.

[Prior art]

In general, an electron emission device including a field emission display (FED) emits electrons from an electron emission source provided to a cathode electrode by using a quantum mechanical tunneling effect, and emits the emitted electrons to a fluorescence provided at the anode electrode. As a display device for realizing a predetermined image by colliding with a layer to emit light, a triode structure having a cathode electrode, a gate electrode, and an anode electrode is widely used.

At this time, the electron emission source is a structure that is formed flat on the cathode electrode in place of the conventional spindt type having a sharp tip is mainly used. The plane type electron emission source is completed by applying a carbon-based material such as carbon nanotubes or graphite to a thick film process such as screen printing and then firing it, and the manufacturing process is relatively simple compared to the spin type electron emission source. In addition, it has an advantage in manufacturing a large area display device.

In general, carbon nanotubes (CNTs) for use in a display are subjected to a post-printing firing process in a paste state, in which xanthan and CNTs of organic matter are buried together and are not effectively exposed on the surface.

Therefore, in order to expose the CNT effectively on the surface, the conventional method serves to build the CNT while contacting and peeling off the tape or polymer resin on the CNT film in order to expose the CNT on the surface. However, this method has a problem in that the polymer resin must be coated on the CNT film and the tape is uniformly attached. This non-uniformity at the time of attachment directly affects the surface shape of the CNT film, and this may have a great influence on the electron emission characteristics and cause non-uniformity of the entire screen. In addition, effective contact may be difficult due to the three-dimensional shape of the CNT surface or the shape of the structure. Since the contact type, residues such as organic matter remain on the substrate or the CNT film, which may adversely affect the vacuum device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to effectively surface-treat a CNT film in the form of gas particles so that the surface of an electron-emitting material can be uniformly treated without leaving foreign substances on a substrate or CNT. It is to provide a method.

Another object of the present invention is to provide a carbon nanotube film obtained by the surface treatment method and an electron emission source manufactured using the same.

Another object of the present invention is to provide a method of manufacturing an electron emission display device including the electron emission source.

In order to achieve the above object, the present invention provides an electron emission source comprising a carbon nanotube having an organic content of 30 to 40% by weight.

In addition, the present invention

Preparing an electron emission source by printing and coating a composition for forming an electron emission source of a flat panel display device including carbon nanotubes (CNT), glass frit, a binder resin, and a solvent;

Spraying and etching the compressed CO ₂ aerosol at the electron emission source

It provides a method for producing an electron emission source comprising a.

In addition, the present invention

(a) forming a cathode electrode on the transparent first substrate;

(b) forming an insulating layer on the entire surface of the first substrate, forming a gate layer on the insulating layer, and then forming holes passing through the gate layer and the insulating layer;

(c) coating the composition for forming an electron emission source including carbon nanotubes on the entire surface of the first substrate and then baking to form an electron emission source; And

(d) spraying and etching the pressurized CO ₂ aerosol on the electron emission source;

It provides a method of manufacturing an electron emission display device comprising a.

In addition, the present invention

(a) forming a gate layer over the transparent first substrate, and then forming an insulating layer;

(b) forming a cathode on the insulating layer;

(c) applying an electron emission source forming composition including carbon nanotubes on the cathode and then baking to form an electron emission source; And

(d) spraying and etching the pressurized CO ₂ aerosol on the electron emission source;

It provides a method of manufacturing an electron emission display device comprising a.

In addition, the present invention provides an electron emission display device including the electron emission source.

The present invention also provides an electron emission display device comprising an electron emission source manufactured by the above method.

Hereinafter, the present invention will be described in more detail.

The present invention sprays an aerosol in which a sublimable gas, such as CO ₂ particles, is dispersed on an electron emission source (CNT film) to etch organic materials and electron emission sources on the surface to effectively expose the CNTs on the surface. There is a feature that provides a method.

In order to effectively expose the CNTs on the surface of the present invention, the sublimable gas under high pressure is sprayed at room temperature and atmospheric pressure, thereby producing sublimable particles having a size of several um. Therefore, when the sublimable particles are sprayed on the electron emission source, the CNT film is peeled off by the instantaneous volume expansion of the particles and the kinetic energy of the particles, and the organic substances contained therein are washed.

This method is generally used in the cleaning of organic substances or pollutants on a substrate, and the present application is applied to the surface treatment method of an electron emission source. The present invention injects a solid sublimable gas at an appropriate pressure and flow rate to the electron emission source to effectively expose the CNTs lying together with the organic residues after firing. According to the present invention, the CO ₂ particles, which have undergone sublimation, are evaporated and removed together with the exfoliated CNTs and the organic material, so that there is no foreign matter remaining on the substrate, and thus, excellent cleaning properties are provided.

Therefore, the present invention can improve the emission current density by effectively surface-treating the electron emission source (CNT film) by adjusting the size, injection pressure and flow rate of the aerosol in which the solid-phase sublimable gas is dispersed, the electron emission source thus obtained The organic content is 30 to 40% by weight (10 to 15% by volume).

As the aerosol in which the sublimable gas in the solid phase is used in the present invention, it is preferable to use, for example, an aerosol in which the carbon dioxide in the solid phase is dispersed (hereinafter referred to as 'CO ₂ aerosol').

In this case, the CO ₂ aerosol is preferably a particle size of 0.1nm to 100 ㎛, the injection pressure is 0.5 to 5 kg, the flow rate is preferably injected at 0.1 to 50 l / min.

Hereinafter, an example of the surface treatment method of the electron emission source of the present invention will be described in more detail with reference to FIG. 1. In FIG. 1, reference numeral 1 denotes a glass substrate deposited with ITO, 2 is a carbon nanotube (Covered CNT) buried with xanthan, 4 is an electron emission source (CNT film), and 5 is carbon which is not buried in xanthan. Nanotubes (Uncovered CNT), 6 is a simplified view of the injection of CO ₂ aerosol.

The present invention is printed coating and firing the composition for forming an electron emission source on a glass substrate deposited with ITO to produce an electron emission source. Through this process, the organic xanthans of the electron emission source and the carbon nanotubes are laid together.

Subsequently, the present invention injects a sublimable gas, preferably an aerosol type CO ₂ gas, compressed at high pressure on the electron emission source as shown in FIG. 1.

CO ₂ , a sublimable gas injected in this process, drops to atmospheric pressure and is formed as CO ₂ particles in the form of dry ice at -75 ° C. by phase change. The CO ₂ particles are converted from the surface liquid phase to the gas phase through the instantaneous volume expansion at the surface to be peeled, to dissolve organic substances or foreign substances on the surface and to remove them simultaneously by the injection gas pressure.

Through the above process, the carbon nanotubes are peeled off to stand, and the carbon nanotubes can be uniformly peeled off by controlling the injection pressure and the generated particle size.

That is, the small particles, aerosol-type CO ₂ can uniformly and effectively surface the electron emission source in the three-dimensional structure.

Carbon nanotubes (CNT) and organic carbon residues peeled off through the above process are removed by sublimated CO ₂ gas so that no foreign matter remains on the substrate.

Therefore, the electron emission efficiency of the electron emission source can be greatly increased by the carbon nanotubes (CNT) effectively exposed on the surface.

Hereinafter, exemplary embodiments of the electron emission display device according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 2 is a partial cross-sectional view of an electron emission display device and an electric field emission display device, according to an exemplary embodiment, but is not limited thereto.

Referring to FIG. 2, in the electron emission display device of the present invention, a first substrate (or cathode substrate) 1 and a second substrate (or anode substrate) 2 having a predetermined size may be formed such that an internal space is formed. They are arranged substantially parallel at intervals and are joined to each other to form a vacuum vessel 4 which is the appearance of the apparatus. The configuration of the electron emission source capable of emitting electrons on the first substrate 1 into the vacuum container, and the emission of electrons emitted from the electron emission source on the second substrate 2 to implement a predetermined image. The configuration of the light emitting portion is formed. The light emitting unit may be configured as follows, for example.

The electron emission source includes a cathode electrode 3 formed on the first substrate 1, an insulating layer 5 formed on the cathode electrode 3, and a gate formed on the insulating layer 5. It is formed on the cathode electrode 3 while being disposed in the holes 5a and 7a formed through the electrode 7 and the insulating layer 5 and the gate electrode 7, and in particular, an electron beam is irradiated to form carbon nanotubes. Made of the cut electron emission source 15. In this case, the gate electrode may be disposed between the upper portion of the first substrate and the insulating layer.

3A to 3E are schematic diagrams illustrating an example of spraying a CO ₂ aerosol after formation of an electron emission source during a manufacturing process of the electron emission display device of the present invention.

Referring to FIG. 3A, as described above, the cathode electrode 3, the insulating layer 5, and the gate electrode 7 are sequentially formed on the rear substrate 1, and the cathode electrode 3 and the gate electrode 7 are sequentially formed. Holes 5a and 7a penetrating through the gate electrode 7 and the insulating layer 5 are formed in the intersecting region. In this case, the rear substrate 1 is made of a transparent glass substrate, and the cathode electrode 3 is made of a transparent conductive film having a high light transmittance, such as indium tin oxide (ITO).

Thereafter, as shown in FIG. 3B, the paste-like electron emission source 19 is applied to the entire upper surface of the first substrate 1 by using a thick film process, and ultraviolet rays are irradiated through the rear surface of the rear substrate 1. Thereby selectively curing the electron emission material 19 on the cathode electrode 3. 3C, after removing the uncured electron emission source material and firing to form the electron emission source 15, the back substrate 1 structure as shown in FIG. 3D can be obtained. Then, as shown in FIG. 3e, the present invention is to CO ₂ gas of the aerosol spray in the electron emission source (15) and etching, that through the etching of the surface with CO ₂ gas in an aerosol form, the carbon nanotube Stand to complete the structure of the rear substrate (1). In addition, the photolithography process is not limited to the above method, but may also be a screen printing process.

The electron emission source 15 is formed on the cathode electrode 3 into the holes 5a and 7a, wherein the electron emission source 15 is formed in a flat shape and preferably made of carbon nano. Tubes can be used.

Of course, the shape 15 of the electron emission source is not limited to the above example, but may be formed while forming a conical shape. That is, in the present invention, the shape of the electron emission source 15 is not limited to a specific case.

Accordingly, the electron emission source configured as described above is provided with the cathode electrode 3 and the gate electrode 7 by the voltage applied to the cathode electrode 3 and the gate electrode 7 from the outside of the vacuum container 4. Electrons are emitted from the electron emission source 15 according to the electric field distribution formed therebetween.

At this time, the surface treatment method of the electron emission source to erect the carbon nanotubes by spraying aerosol-type CO ₂ to the electron emission source of the present invention is as described in FIG.

In the present invention, the composition used when forming the electron emission source preferably includes carbon nanotubes (CNT), an inorganic powder, a binder resin, and an organic solvent, and may be in the form of a paste or slurry.

In the present invention, the carbon nanotube is used in an amount of 20 to 40% by weight in the composition.

The inorganic powder, the binder resin and the organic solvent can be used that is usually used in the preparation of the composition for electron emission source formation, it is not particularly limited. In the present invention, a photosensitive resin and an initiator for UV may be further added as necessary.

The cathode electrode 3 is formed along a direction of the first substrate 1 by taking a predetermined pattern, for example, a stripe shape, and the insulating layer 5 covers the cathode electrode 3 while It is disposed on the first substrate 1 as a whole.

Further, on the insulating layer 5, a plurality of gate electrodes 7 having holes 5a and through holes 7a formed in the insulating layer 5 are formed. It is formed by maintaining a stripe shape at an arbitrary interval in the direction orthogonal to the cathode electrode (3).

Compared with the structure of such an electron emission source, the structure of the said light emitting part is the anode electrode 11 formed in the one surface (surface facing the said 1st board | substrate) of the said 2nd board | substrate 2, and this anode electrode 11 And R, G, and B fluorescent films 13 formed thereon.

The anode electrode 11 is made of a transparent material such as indium tin oxide (ITO) and maintains a stripe pattern that is elongated in a direction parallel to the longitudinal direction of the cathode electrode 3 on the second substrate 2. A plurality of fluorescent films 13 may be formed at random intervals, and the fluorescent film 13 may be formed on the anode electrode 11 through a manufacturing method such as electrophoresis, spin printing, or spin coating.

In addition, although not shown in the drawings, the present invention may provide an electron emission display device manufactured by forming an electron emission source in the same manner as described above and including the following steps.

That is, the manufacturing method of the electron emission display device of the present invention

(a) forming a gate layer over the transparent first substrate, and then forming an insulating layer; (b) forming a cathode on the insulating layer; (c) applying an electron emission source forming composition including carbon nanotubes on the cathode and then baking to form an electron emission source; And (d) spraying and etching the CO ₂ aerosol compressed at high pressure on the electron emission source.

Hereinafter, preferred examples and comparative examples of the present invention are described. The following examples are described for the purpose of more clearly expressing the present invention, but the contents of the present invention are not limited to the following examples.

(Example 1)

A paste composition was prepared by mixing and stirring 0.2 g of carbon nanotubes, 0.05 g of glass frit, 20 g of acrylate resin with a binder resin, and 2 g of butyl carbitol acetate as a solvent. Thereafter, the composition was printed on a glass substrate on which ITO was deposited by screen printing, and then fired at a temperature of 600 ° C. to produce an electron emission source.

Then, the surface of the electron emission source was treated by spraying a CO ₂ aerosol with a particle size of 0.5 nm compressed at high pressure at a flow rate of 10 L / mindm in 1 kg of injection pressure.

(Comparative Example 1)

A paste composition was prepared by mixing and stirring 0.2 g of carbon nanotubes, 0.05 g of glass frit, 20 g of acrylate resin with a binder resin, and 2 g of butyl carbitol acetate as a solvent. Thereafter, the composition was printed on a glass substrate on which ITO was deposited by screen printing, and then fired at a temperature of 600 ° C. to produce an electron emission source.

Experimental Example

For Example 1 and Comparative Example 1, the amount of current for the electron emission source was measured by the bipolar tube method, and the results are shown in FIG. 4. As shown in the results of FIG. 4, in the case of Example 1 of the present invention, carbon nanotubes erected in comparison with Comparative Example 1 in which carbon nanotubes are buried by organic xanthan according to a conventional method by removing organic xanthan by CO ₂ aerosol By increasing, it shows uniform electron emission characteristic, and in particular, the electron emission density of 75% is improved in an electric field of 5 V / um than Comparative Example 1, and it can be seen that the electron emission characteristic is very excellent.

As described above, the present invention treats the surface of the electron emission source by using a sublimable gas such as CO ₂ gas, and effectively establishes carbon nanotubes buried with organic xanthan, thereby greatly improving electron emission characteristics. Can be. Accordingly, an electron emission display device having excellent electron emission characteristics can be provided.

Figure 1 shows a schematic view of the carbon nanotube stripping process of the electron emission source by the CO ₂ aerosol of the present invention.

2 is a partial cross-sectional view showing an example of the electron emission display device of the present invention.

3A to 3E are schematic diagrams illustrating an example of spraying a CO ₂ aerosol after formation of an electron emission source during a manufacturing process of the electron emission display device of the present invention.

4 shows the IV characteristics of an electron emission source (Example 1) surface-treated by etching with a CO ₂ aerosol and a surface-treated electron emission source (Comparative Example 1) according to the present invention.

Claims (14)

An electron emission source comprising carbon nanotubes having an organic content of 30 to 40% by weight. The electron emission source according to claim 1, wherein the electron emission source is obtained by surface treatment with sublimable particles containing a CO ₂ aerosol. The electron emission source of claim 1, wherein the CO ₂ aerosol has a particle size of 0.1 nm to 100 μm. Preparing an electron emission source by printing and coating a composition for forming an electron emission source of a flat panel display device including carbon nanotubes (CNT), glass frit, a binder resin, and a solvent; Spraying and etching the compressed CO ₂ aerosol at the electron emission source Method of producing an electron emission source comprising a. The method of claim 4, wherein the sublimable gas is a CO ₂ aerosol having a particle size of 0.1 nm to 100 μm. The method of manufacturing an electron emission source according to claim 4, wherein the sublimable gas is in a spray pressure of 0.5 to 5 kg and a flow rate is injected at 0.1 to 50 l / min. (a) forming a cathode electrode on the transparent first substrate; (b) forming an insulating layer on the entire surface of the first substrate, forming a gate layer on the insulating layer, and then forming holes passing through the gate layer and the insulating layer; (c) coating the composition for forming an electron emission source including carbon nanotubes on the entire surface of the first substrate and then baking to form an electron emission source; And (d) spraying and etching the pressurized CO ₂ aerosol on the electron emission source; Method of manufacturing an electron emission display device comprising a. The method of claim 7, wherein the CO ₂ aerosol has a particle size of 0.1 nm to 100 μm. 8. The method of claim 7, wherein the CO ₂ aerosol is in the injection pressure of 0.5 to 5 kg, the flow rate is injected at 0.1 to 50 l / min. (a) forming a gate layer over the transparent first substrate, and then forming an insulating layer; (b) forming a cathode on the insulating layer; (c) applying an electron emission source forming composition including carbon nanotubes on the cathode and then baking to form an electron emission source; And (d) spraying and etching the pressurized CO ₂ aerosol on the electron emission source; Method of manufacturing an electron emission display device comprising a. The method of claim 10, wherein the CO ₂ aerosol has a particle size of 0.1 nm to 100 μm. The method according to claim 10, wherein the CO ₂ aerosol is in the injection pressure of 0.5 to 5 kg, the flow rate is injected at 0.1 to 50 L / min. An electron emission display device comprising the electron emission source of any one of claims 1 to 3. An electron emission display device comprising an electron emission source manufactured by the method of claim 4.