KR20070010661A - An electron emission source, a preparing method thereof, and an electron emission device using the same - Google Patents

Abstract

An electron emission source, a preparing method thereof, and an electron emission device using the same are provided to simplify a paste manufacturing process by using an Ag-contained organic composite. An electron emission source(160) includes a carbon-based material and Ag having an average particle diameter of 2 to 200nm. The Ag is 0.25 to 10 weight percent when the carbon-based material is 1 weight percent. The electron emission source further includes frit of 0.25 to 10 weight percent when the carbon-based material is 1 weight percent. The frit is formed of tin oxide-SnO-P2O5. The carbon-based material is one or more elements selected from a carbon nano-tube, graphite, diamond, fullerene, and silicon carbide.

Description

An electron emission source, a method of manufacturing the same, and an electron emission device employing the same

1 is a cross-sectional view schematically showing an embodiment of an electron emitting device of the present invention,

2 and 3 are diagrams showing the electron emission characteristics of the electron emission source according to Example 1 and Comparative Example 1 of the present invention.

<Short description of drawing symbols>

110: lower substrate 120: cathode electrode

130: insulator layer 140: gate electrode

160: electron emission source 170: phosphor layer

180: anode electrode 190: upper substrate

The present invention relates to an electron emission source, a method of manufacturing the same, and an electron emission device employing the same, and more particularly, to an electron emission source having improved electron emission performance, a method of manufacturing the same, and an electron emission device employing the same.

An electron emission device emits electrons from an electron emission source of a cathode electrode by applying a voltage between the anode electrode and the cathode electrode to form an electric field, and impinges the electrons on a fluorescent material on the anode electrode side to emit light. It is a display device.

Carbon-based materials including carbon nanotubes (CNTs), which have excellent electronic conductivity, have excellent conductivity and field concentration effects, low work function, and excellent field emission characteristics, so that low-voltage driving is possible and large area is possible. It is expected to be an ideal electron emission source for electron emission devices.

The method for producing an electron emission source containing carbon nanotubes includes, for example, a carbon nanotube growth method using a CVD method, a paste method using a composition for forming an electron emission source containing carbon nanotubes, and the like.

When the paste method is used, the manufacturing cost is low and the electron emission source can be formed in a large area.

However, when manufacturing a paste using only carbon nanotubes, it is common to add a certain amount or more of silver powder to the paste due to poor flowability. Thus, the addition of the silver powder improves the contact between the carbon nanotubes or the contact between the substrate and the carbon nanotubes, and reduces the carbon nanotubes falling from the substrate during use, thereby improving the electron emission characteristics and lifetime.

However, adding silver powder makes it difficult to disperse carbon nanotubes and silver powder.

There is a problem that is difficult.

The technical problem to be solved by the present invention is to solve the problems described above to improve the dispersing phase, the composition for forming an electron emission source is easy to manufacture the paste, and the contact resistance between the carbon nanotubes and the electrode by using this to improve the electron emission ability It is to provide an electron emission element having improved reliability by employing the electron emission source and its manufacturing method and the electron emission source.

In order to achieve the above technical problem, in the present invention; And

It provides an electron emission source comprising a silver (Ag) of 2 to 100nm particle average particle diameter.

Another technical problem of the present invention is a first substrate and a second substrate disposed to face each other;

A cathode electrode formed on the first substrate;

The aforementioned electron emission source formed to be electrically connected to a cathode electrode formed on the substrate;

An anode electrode formed on the second substrate; And

And a fluorescent layer which emits light by electrons emitted from the electron emission source.

Another technical problem of the present invention is a carbon-based material;

A vehicle consisting of a resin component and a solvent component; And

It is made by the composition for electron emission source formation containing silver containing organic compound.

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

The composition for forming an electron emission source of the present invention contains a carbon-based material, a vehicle, and a silver-containing organic compound that is easily dispersed with a carbon-based material such as the carbon-based material.

Specific examples of the silver-containing organic compound include Ag (bpp) ClO ₄ , where bpp is 1,3-bis (4-pyridyl) propane.

The frit may be further added to the composition, and non-limiting examples of the frit include tin oxide-phosphorus pentoxide (SnO-P ₂ O ₅ ) and the like.

The content of the silver-containing organic compound is preferably 5 to 100 parts by weight, more preferably 10 to 60 parts by weight based on 1 part by weight of the carbonaceous material.

In the present invention, when the silver-containing organic compound is added to the electron emission source forming composition, the silver-containing organic compound has excellent dispersibility with carbon nanotubes, thereby making it possible to manufacture an electron emission source having improved electron emission ability.

In the present invention, when frit is added to the composition for forming an electron emission source, the content of frit is preferably 0.25 to 10 parts by weight based on 1 part by weight of the carbon-based material. If the content of frit is less than 0.25 parts by weight, the adhesion of the electron emission source is lowered, and if it is more than 10 parts by weight, the electron emission characteristics are lowered, which is not preferable.

The carbon-based material used in the present invention has excellent conductivity and electron emission characteristics, and serves to excite the phosphor by emitting electrons to the fluorescent layer of the anode part when the electron emission device is operated. Non-limiting examples of such carbon-based materials are carbon nanotubes, graphite, diamond, fullerenes, silicon carbide and the like, and carbon nanotubes are most preferred.

The vehicle included in the composition for forming an electron emission source of the present invention serves to control the printability and viscosity of the composition for forming an electron emission source. The vehicle may consist of a resin component and a solvent component. The resin component may be, for example, a cellulose resin such as ethyl cellulose, nitro cellulose or the like; Acrylic resins such as polyester acrylate, epoxy acrylate, urethane acrylate and the like; At least one of a vinyl-based resin such as polyvinyl acetate, polyvinyl butyral, polyvinyl ether, and the like may be included, but is not limited thereto. Some of the resin components as described above may simultaneously serve as a photosensitive resin.

The solvent component is, for example, at least one of terpineol, butyl carbitol (BC), butyl carbitol acetate (BCA), toluene and texanol It may include. Among these, it is preferable to contain terpineol.

The content of the resin component may be 1 to 5 parts by weight, more preferably 2 to 3 parts by weight based on 1 part by weight of the carbon-based material.

On the other hand, the content of the solvent component may be 5 to 15 parts by weight, preferably 8 to 12 parts by weight based on 1 part by weight of the carbon-based material. Herein, when the content of the vehicle consisting of the resin component and the solvent component is outside the above range, there may be a problem in that printability and flowability of the composition for forming an electron emission source are lowered. In particular, when the content of the vehicle exceeds the above range, there is a problem that the drying time may be too long.

In addition, the composition for forming an electron emission source of the present invention may further include one or more selected from a photosensitive resin, a photoinitiator, and a filler as necessary.

In the composition for forming an electron emission source, the photosensitive resin is a material used for patterning an electron emission source. Non-limiting examples of the photosensitive resin include acrylate monomers, benzophenone monomers, acetophenone monomers, or thioxanthone monomers, and more specifically epoxy acrylates, polyester acrylates, 2,4 -Diethyloxanthone (2,4-diethyloxanthone), 2,2-dimethoxy-2-phenylacetophenone, etc. can be used. The content of the photosensitive resin may be 3 to 10 parts by weight, preferably 5 to 8 parts by weight, based on 1 part by weight of the carbon-based material. When the content of the photosensitive resin is less than 3 parts by weight, the exposure sensitivity is lowered. When the content of the photosensitive resin is more than 10 parts by weight, the development is not good, which is not preferable.

The photoinitiator serves to initiate crosslinking of the photosensitive resin when the photosensitive resin is exposed. Non-limiting examples of such photoinitiators include benzophenone and the like. The content of the photoinitiator may be 3 to 10 parts by weight, preferably 5 to 8 parts by weight based on 1 part by weight of the carbon-based material. If the content of the photoinitiator is less than 3 parts by weight, efficient crosslinking may not be achieved, which may cause a problem in pattern formation, and if it exceeds 10 parts by weight, it may cause a rise in manufacturing cost.

The filler is a material that serves to further improve the conductivity of the inorganic material having a nano-size that is not sufficiently adhered to the substrate, non-limiting examples thereof include Ag, Al, and the like.

Hereinafter, a method of manufacturing an electron emission source using the composition for forming an electron emission source will be described.

First, a composition for forming an electron emission source is prepared with the components and contents as described above. Detailed description of the composition for forming an electron emission source is the same as described above, and thus will be omitted.

Thereafter, the provided composition for forming an electron emission source is printed on a substrate. The "substrate" is a substrate on which an electron emission source is to be formed, which may be different depending on the electron emission element to be formed, which is easily recognized by those skilled in the art. For example, the "substrate" may be a cathode when manufacturing an electron emission device having a gate electrode between a cathode and an anode, and an electron emission device having a gate electrode disposed below the cathode. In manufacturing, the insulating layer may be an insulating layer that insulates the cathode and the gate electrode.

The step of printing the composition for forming an electron emission source is different depending on the case of including the photosensitive resin and the case of not including the photosensitive resin. First, when the composition for electron emission source formation contains photosensitive resin, a separate photoresist pattern is unnecessary. That is, a composition for forming an electron emission source containing a photosensitive resin is applied onto a substrate, and then exposed and developed according to the desired electron emission source formation region.

On the other hand, when the composition for electron emission source formation does not contain photosensitive resin, the photolithography process using a separate photoresist pattern is required. That is, a photoresist pattern is first formed using a photoresist film, and then the composition for forming an electron emission source is supplied by printing using the photoresist pattern.

The composition for forming an electron emission source printed as described above is subjected to a firing step in a nitrogen gas atmosphere or a mixed gas atmosphere of oxygen and nitrogen. Through such a firing step, the carbon-based material in the composition for forming an electron emission source may improve adhesion to the substrate, the vehicle may be volatilized and removed, and other inorganic binders may be melted and solidified to contribute to improving durability of the electron emission source. It becomes possible.

The firing temperature should be determined in consideration of the volatilization temperature and time of the vehicle included in the composition for forming an electron emission source. Typical firing temperatures are 350 to 500 ° C, preferably 450 ° C. If the firing temperature is less than 350 ℃ may cause a problem that the volatilization such as a vehicle is not sufficiently made, if the firing temperature exceeds 500 ℃ may cause a problem that the manufacturing cost rises, the substrate may be damaged.

The calcined product thus fired undergoes an activation step as necessary. According to one embodiment of the activation step, after applying a solution that can be cured in the form of a film through a heat treatment process, for example, an electron emission source surface treatment agent containing a polyimide-based polymer on the firing result, and then heat treatment Then, the film formed by the heat treatment is peeled off. According to another embodiment of the activation step, the activation process may be performed by forming an adhesive part having an adhesive force on the surface of the roller driven by a predetermined driving source and pressing the surface of the firing product at a predetermined pressure. Through this activation step, the nano-sized inorganic material can be controlled to be exposed or vertically aligned to the electron emission source surface.

The electron emission source of the present invention obtained according to the above manufacturing process includes a carbon-based material and nano-sized silver, that is, nano-sized Ag having a particle average particle diameter of 2 to 100 nm. In some cases, frit may be further included.

Such an electron emission source of the present invention can be used for an electron emission element used as a display element or a backlight unit.

One embodiment of an electron emission device having an electron emission source of the present invention as described above is referred to FIG. 1.

1 schematically shows an electron emitting device having a triode structure among various electron emitting devices according to the present invention. The electron emission device 200 illustrated in FIG. 1 includes an upper plate 201 and a lower plate 202, and the upper plate is an upper electrode 190 and an anode electrode 180 disposed on the lower surface 190a of the upper substrate. And a phosphor layer 170 disposed on the bottom surface 180a of the anode electrode.

The lower plate 202 has a lower surface substrate 110 arranged in parallel with the upper substrate 190 at predetermined intervals to have an inner space, and a cathode electrode disposed in a stripe shape on the lower substrate 110. 120, a gate electrode 140 arranged in a stripe shape to intersect the cathode electrode 120, an insulator layer 130 disposed between the gate electrode 140 and the cathode electrode 120, and the insulator layer An electron emission source hole 169 formed in a portion of the gate electrode 140 and the gate electrode 140, and disposed in the electron emission source hole 169 to conduct electricity to the cathode electrode 120 and to be lower than the gate electrode 140. It has an electron emission source 160 disposed at a height. Detailed description of the electron emission source 160 is the same as described above, and thus will be omitted.

The upper plate 201 and the lower plate 202 are maintained in a vacuum at a pressure lower than atmospheric pressure, and the spacer 192 supports the pressure between the upper plate and the lower plate generated by the vacuum and partitions the light emitting space 210. It is disposed between the upper plate and the lower plate.

The anode electrode 180 applies a high voltage required for acceleration of electrons emitted from the electron emission source 160 to allow the electrons to collide with the phosphor layer 170 at high speed. The phosphor of the phosphor layer is excited by the electrons and emits visible light while falling from a high energy level to a low energy level.

The gate electrode 140 serves to facilitate the emission of electrons from the electron emission source 160, and the insulator layer 130 partitions the electron emission source hole 169 and the electrons. It serves to insulate the emission source 160 and the gate electrode 140.

The electron-emitting device of the present invention has been described by taking an electron-emitting device having a triode structure as shown in FIG. In addition, it is possible to prevent damage to the electron emission element in which the gate electrode is disposed below the cathode electrode, the gate electrode and / or the cathode electrode due to the arc that is assumed to be caused by the discharge phenomenon, and to focus the electrons emitted from the electron emission source. It can also be used for electron emitting devices with grids / meshes to ensure the safety. On the other hand, it is also possible to apply the structure of the electron emitting device to the display device.

Hereinafter, the present invention will be described with reference to the following examples, but the present invention is not limited to the following examples.

Example  One

40g of terpineol, 1g of carbon nanotubes (MWNT, manufactured by ILJIN Nanotech Co., Ltd.), 1g of frit (8000L, manufactured by Emerging Industries), 5g of polyester acrylate, 5g of photosensitive resin (TMPTA, Aldrich), photoinitiator (HS-188, 5g of Dongyang Ink Co., Ltd. was added thereto, and then 20g of Ag (bpp) ClO ₄ was added thereto, followed by stirring to prepare a composition for forming an electron emission source.

The composition for forming an electron emission source was printed on an electron emission source formation region on a substrate provided with a Cr gate electrode, an insulating film, and an ITO electrode, and then using a parallel exposure machine with an exposure energy of 2000 mJ / cm ² using a pattern mask. Investigate. After exposure, it was developed using acetone, and fired in the presence of a temperature of 450 ° C. and a mixed gas of oxygen and nitrogen (oxygen concentration of about 1000 ppm) to form an electron emission source.

Subsequently, a substrate using ITO as a fluorescent film and an anode electrode was arranged so as to be oriented with the substrate on which the electron emission source was formed, and a spacer for maintaining a cell gap between substrates was formed between both substrates to complete an electron emission device.

Comparative example  One

Except for using 20g of Ag powder instead of 20g of Ag (bpp) ClO ₄ , it was carried out in the same manner as in Preparation Example 1 to prepare an electron emission source composition and to complete the electron emitting device in the same process.

The current densities of Example 1 and Comparative Example 1 were measured using a pulse power source and an ammeter. 2 shows current density according to an electric field of an electron emission device manufactured according to Comparative Example 1. FIG. 3 shows a current density according to an electric field of an electron emission device manufactured according to Example 1. FIG. In Comparative Example 1 having an electron emission source to which ordinary Ag powder was added, a current density of 45 mA / cm ² was obtained at 5 V / µm, while in Example 1 using organic Ag, 70 mA / cm ² at 5 V / µm As a result, it was found that Example 1 has an increased current density of about 56% compared to Comparative Example 1. Therefore, it was confirmed that when the organic Ag was added, an electron emitting device having higher electron emission characteristics could be produced than when Ag powder was added.

The composition for forming an electron emission source of the present invention contains a silver-containing organic compound, which facilitates mixing and dispersing with a carbon-based material such as carbon nanotubes, thereby facilitating paste production. Therefore, the use of such a paste reduces the contact resistance between the carbon nanotubes and the cathode electrode, thereby manufacturing an electron emission source having improved electron emission characteristics. By using the electron emission source, an electron emission device having improved reliability can be obtained.

Claims (10)

Carbon-based materials; And An electron emission source comprising: silver (Ag) having a particle average particle diameter of 2 to 100 nm. The electron emission source of claim 1, wherein the content of silver is 5 to 100 parts by weight based on 1 part by weight of the carbonaceous material. The electron emission source of claim 1, further comprising 0.25 to 10 parts by weight of frit based on 1 part by weight of the carbonaceous material. The electron emission source according to claim 3, wherein the frit is tin oxide-phosphorus pentoxide (SnO-P ₂ O ₅ ). The electron emission source of claim 1, wherein the carbonaceous material is at least one selected from carbon nanotubes, graphite, diamond, fullerenes, and silicon carbide. A first substrate and a second substrate disposed to face each other; A cathode electrode formed on the first substrate; The electron emission source of any one of claims 1 to 5 formed to be electrically connected to the cathode electrode formed on the substrate; An anode electrode formed on the second substrate; And And a fluorescent layer that emits light by electrons emitted from the electron emission source. Carbon-based materials; A vehicle consisting of a resin component and a solvent component; And A composition for forming an electron emission source comprising a silver-containing organic compound. The method of claim 7, wherein the silver-containing organic compound, Ag (bpp) ClO ₄ , wherein bpp is 1,3-bis (4-pyridyl) propane). 8. The composition of claim 7, wherein frit is further included. The composition of claim 7, wherein the content of the silver-containing organic compound is 5 to 100 parts by weight based on 1 part by weight of the carbonaceous material.

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