KR100778104B1 - Carbon nanotube Paste Composite for Electric Field Emitting Display Device - Google Patents

Abstract

The present invention provides a carbon nanotube paste composition for a field emission display device comprising a dielectric material capable of spontaneous polarization with a filler in the carbon nanotube paste composition for a field emission display device. According to the present invention, a field emission display device capable of driving a low voltage and high current in implementing an electron emission device can be manufactured.

Description

Carbon nanotube paste composition for field emission display device {Carbon nanotube Paste Composite for Electric Field Emitting Display Device}

1 is a structural diagram of a conventional field emission display device

Figure 2 is a comparison of electron emission characteristics results of the electron emission source using the dielectric material according to the present invention

Figure 3 is a comparison of the results of long-term electron emission characteristics of the electron emission source using the dielectric material according to the present invention

The present invention relates to a carbon nanotube paste composition for a field emission display device, and more particularly, to a carbon nanotube paste composition for improving field emission characteristics by using field emission characteristics of a dielectric material. .

In general, an electron emission device includes a method using a hot cathode and a cold cathode as an electron source.

In general, an electron emisson display is a flat display device in which electrons emitted toward a first substrate are collided with a phosphor layer formed on a second substrate to generate a predetermined image by using light emission thereof. For example, there are a method using a hot cathode and a method using a cold cathode as an electron source.

Among them, the cold-cathode electron emission display device includes a field emitter array (FEA) type electron emission display device, a metal-insulator-metal type electron emission display device, and a metal-insulator-semiconductor (MIS) type electron. Emission display devices and surface conduction type electron emission display devices and the like are known.

The electron emission display device forms an electron emission source with materials that emit electrons when an electric field is applied, and has a predetermined display with electrodes for controlling electron emission. The electron emission display device is greatly affected by the overall quality of the display device according to the characteristics of the electron emission source.

Referring to FIG. 1, in a conventional cold cathode electron emission display device, a front substrate 2 and a back substrate 3 are provided with a vacuum gap held by a spacer 1 interposed therebetween, and the front substrate ( An anode electrode 4 coated with a phosphor is formed in 2), and a cathode electrode 5 is formed in the back substrate 3. In addition, an electron emission source 6 having a metal tip shape electrically connected to the cathode electrode 5 is formed.

Initially, the electron emission source 6 used a micro tip type having a distal tip mainly made of molybdenum (Mo) or the like. However, in order to manufacture an electron emission display device having a micro-tip type electron emission source 6, a semiconductor process must be used, and thus, the manufacturing process is complicated, requires a high level of technology and expensive equipment, and a large screen display device. It has a hard disadvantage.

In order to overcome this phenomenon, efforts have been made to use carbon nanotubes having high electron emission efficiency and stability as electron emission sources.

When carbon nanotubes are to be used as an electron emission source, a direct growth method, an electrophoresis method, a screen printing method, or the like is being studied as a method of manufacturing the carbon nanotubes. However, the direct growth method is difficult to manufacture due to the constraints of the synthesis conditions (eg, temperature) of the carbon nanotubes to prevent deformation of the substrate, and the electrophoresis method makes it difficult to uniformly form the carbon nanotubes over the entire surface of the substrate. There are disadvantages.

On the other hand, the screen printing method is a method of preparing a paste by mixing carbon nanotubes with a resin and an organic solvent, and forming the electron emission source by screen printing the paste on a substrate. This method is easier to apply to large area substrates and has simpler process conditions than the direct growth method or the electrophoresis method. In order to form an electron emission source made of carbon nanotubes in a desired position, a screen printing paste containing an additive additive for dispersing and bonding the organic binder material and the carbon nanotubes to the substrate and performing heat treatment to remove the organic material A rubbing process is applied to impart orientation to the carbon nanotubes whose process and orientation directions are not constant.

The performance of the final electron emitter is affected by the quality of each raw material and various factors applied during the process. It is very important to have a high electron emission amount while the voltage for electron emission is low in order to be applied to actual devices such as LCD (Liquid Crystal Display) light source and FED (Field Emission Display). However, when the screen printing method is used, the orientation of the carbon nanotubes decreases, so the amount of the carbon nanotubes emitting the actual electrons decreases and the voltage at which the electrons start emitting the electrons increases. In order to make excellent electron emission sources while making the most of the advantages of screen printing, which is economical and enables large-area panels, core technologies that can compensate for these disadvantages are required.

The maintenance of the screen printing process itself is important for producing a good electron emission source using the screen printing method, but the control of the carbon nanotube paste composition used for screen printing is very important. In other words, a paste manufacturing process is easy and a control of a composition capable of easily emitting a high current at a low voltage is required.

The present invention has been made to solve the problems of the prior art as described above, the object of the present invention is to provide a carbon nanotube paste composition for a field emission display device that enables low voltage, high current drive in implementing an electron emission device have.

As a means for achieving the above object, the present invention provides a carbon nanotube paste composition for a field emission display device comprising a dielectric material capable of spontaneous polarization as a filler. to provide.

The present invention preferably provides a carbon nanotube paste composition for a field emission display device, wherein the dielectric material is contained in an amount of 10 to 80% by weight.

The present invention preferably provides a carbon nanotube paste composition for a field emission display device, wherein the dielectric material is one selected from the group consisting of BaTiO ₃ , (Ba, Sr) TiO ₃ , SrTiO ₃ , PZT, and PLZT. do.

The present invention provides a carbon nanotube paste composition for a field emission display device comprising 10 to 80% by weight of carbon nanotubes, 10 to 80% by weight of an organic vehicle, and 10 to 80% by weight of a dielectric material.

The present invention preferably provides a carbon nanotube paste composition for field emission display device, characterized in that the inorganic binder is added up to 70% by weight.

Hereinafter, the content of the present invention in more detail as follows.

The carbon nanotube paste composition for a field emission display device according to the present invention includes various components that have been generally applied in addition to the material used as a filler. These components include carbon nanotube powders, organic vehicles, and inorganic binders as the main raw materials.

The carbon nanotube powder is not particularly limited, and all kinds of carbon nanotubes of Iljin Nanotech Co., Ltd. (Korea), which are currently commercially available, may be used. These carbon nanotube contents are not particularly limited and may be applied in an amount of about 10 to 80% by weight based on the weight of the entire composition.

Organic vehicles are materials that are applied to make the compositions printable, for example ethyl cellulose, nitro cellulose, acrylates, polystyrenes, poly methacrylate compositions, and the like. The content of these organic vehicles is not particularly limited, and may be about 10 to 80% by weight based on the weight of the entire composition.

The inorganic binder is a material that can be applied to attach the respective compositions to the substrate, for example, frit glass, SOG, and the like. The content of these inorganic binders is not particularly limited, and it is sufficient to apply up to 70% by weight with respect to the total weight of the composition.

Another dielectric material according to the present invention can be applied to replace the conventional fillers of metals such as alumina or copper, so that the electron emission can be greatly increased by independently emitting electrons without inhibiting the electron emission characteristics generated from the carbon nanotubes. This feature enables low voltage, high current driving in real electron emission devices.

The dielectric material which can be used in the present invention does not require special limitation as long as it causes spontaneous polarization, for example barium titanate (BaTiO ₃ ), barium strontium titanate ((Ba, Sr) TiO ₃ ), SrTiO ₃ , dielectric material such as PZT, PLZT can be used.

The content in the composition of these dielectric materials is not particularly limited, and it is sufficient to apply up to 10 to 80% by weight based on the total weight of the composition.

Carbon nanotube paste according to the present invention is a carbon nanotube, organic vehicle, optionally inorganic binder, dielectric material filler is mixed in a predetermined ratio, the primary mixing by using a mortar, etc., followed by secondary mixing using a three roll mill or the like The final carbon nanotube paste can be prepared.

2 and 3, the carbon nanotube paste composition prepared as described above shows a significant increase in the amount of current during field emission, compared to the case of using alumina, copper, or the like, which is a conventional metal filler. It can be seen that even when phosphorus is used, the decrease in the amount of electron emission is small.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, these examples are only for illustrating the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples.

<Example 1>

Multi-walled carbon nanotubes (ILJIN NanoTech), organic vehicles (nitro cellulose), frit glass, and barium titanate (BaTiO ₃ ) as a dielectric material filler were mixed at a weight ratio of 1: 5: 1: 1. At this time, the primary carbon nanotube paste was prepared by secondary mixing using a three roll mill after primary mixing using induction.

<Example 2>

Barium strontium titanate ((Ba, Sr) TiO ₃ ) as a filler for multi-walled carbon nanotubes (ILJIN Nanotech), organic vehicles (nitro cellulose), frit glass and dielectric materials Mix by weight ratio. At this time, the primary carbon nanotube paste was prepared by secondary mixing using a three roll mill after primary mixing using induction.

Comparative Example 1

A multi-walled carbon nanotube (ILJIN Nanotech), an organic vehicle (nitro cellulose), frit glass, alumina (Al ₂ O ₃ ) or Cu as a filler were mixed in a weight ratio of 1: 5: 1: 1.5, respectively. At this time, the primary carbon nanotube paste was prepared by secondary mixing using a three roll mill after primary mixing using induction.

<Example 3>

An electron emission source for a field emission display device was manufactured using the carbon nanotube paste prepared in Examples 1, 2, and Comparative Example 1. Each paste was applied to the silver electrode by screen printing, and then heat-treated at 380 ° C. for 30 minutes while flowing N ₂ gas at 4 L / min. The obtained electron emission source was then rubbed using a taping method.

Experimental Example 1

In order to observe the electron emission characteristics of the electron emission sources obtained through Example 3, field emission was attempted using the gold electrode as an anode in an environment of a vacuum chamber having a vacuum degree of ˜10 ⁻⁵ torr, and IV characteristics were measured. The results are shown in FIG. As a result, it was confirmed that the barium titanate and barium strontium titanate were significantly increased in the field emission when the alumina was used as the filler.

Experimental Example 2

In order to observe stability among electron emission characteristics of the electron emission sources obtained through Example 3, IV characteristics during field emission were repeatedly measured using a gold electrode as an anode in an environment of a vacuum chamber having a vacuum degree of ˜10 ⁻⁵ torr. As a result, it is shown in Figure 3 by comparing the observed decrease in the amount of electron emission. As a result, when barium titanate and barium strontium titanate were used as fillers, it was confirmed that the decrease in electron emission amount by repeated measurement was smaller than when metals such as Cu were used as fillers.

As described above, according to the present invention, there is an effect of greatly improving the electron emission efficiency of the electron emission source produced by screen printing the carbon nanotube paste. This has the advantage of enabling low voltage high current driving in realizing the electron emission device by increasing the amount of electron emission by independently emitting electrons without inhibiting the electron emission characteristics generated from the carbon nanotubes. In addition, it does not affect the deterioration of the carbon nanotubes, there is an advantage to improve the long-term drive characteristics.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that it can be changed.

Claims (6)

delete In the carbon nanotube paste composition for a field emission display device, A carbon nanotube paste composition for a field emission display device comprising 10 to 80% by weight of a dielectric material capable of spontaneous polarization as a filler. The carbon nanotube paste of claim 2, wherein the dielectric material capable of spontaneous polarization is one selected from the group of BaTiO ₃ , (Ba, Sr) TiO ₃ , SrTiO ₃ , PZT, and PLZT. Composition. A carbon nanotube paste composition for a field emission display device comprising 10 to 80% by weight of carbon nanotubes, 10 to 80% by weight of an organic vehicle, and 10 to 80% by weight of a dielectric material capable of spontaneous polarization. The carbon nanotube paste composition for a field emission display device according to claim 4, wherein the inorganic binder is added at most 70 wt%. The carbon nanotube paste according to claim 4, wherein the dielectric material capable of spontaneous polarization is one selected from the group of BaTiO ₃ , (Ba, Sr) TiO ₃ , SrTiO ₃ , PZT, and PLZT. Composition.

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