KR100874453B1 - Method of forming electron emission source of field emission display - Google Patents

Abstract

The present invention relates to a method for forming an electron emission source of a field emission display device which can be uniformly applied to the surface of an electron emission source and easily applied to fabrication of a large display.

An electron emission source forming method includes forming cathode electrodes on a substrate; Preparing a carbon film by sequentially laminating an adhesive layer, a carbon layer including a photosensitive material, and a protective film on the transparent base film; Removing the protective film and laminating the carbon film on the substrate such that the carbon layer is in contact with the cathode electrode; Arranging an exposure mask on the carbon film, irradiating ultraviolet light to cure the carbon layer, and fixing the carbon layer on the cathode electrode; Removing the base film, removing the uncured carbon layer, and then heat treating.

Description

Method of forming an electron emission source of a field emission display device {PRODUCING METHOD OF ELECTRON EMISSION SOURCE FOR FIELD EMISSION DISPLAY DEVICE}

1 to 5 are schematic diagrams at each detailed step for explaining a method for forming an electron emission source of a field emission display device according to a first embodiment of the present invention.

6 to 8 are schematic diagrams at each detailed step for explaining an electron emission source forming method of a field emission display device according to a second embodiment of the present invention;

9 and 10 are partially exploded perspective views of a field emission display device having an electron emission source fabricated by the method for forming an electron emission source according to the present invention, respectively.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an electron emission source of a field emission display, and more particularly, to form an electron emission source of a field emission display device, which can be applied to the surface of an electron emission source evenly and to be easily applied to fabrication of a large display. It is about a method.

The field emission display device, which is a kind of flat panel display device, used a spindt type electron emission source in which a tip was formed by stacking materials such as molybdenum or silicon in the early stage. Due to the ultra-fine structure, the manufacturing method is complicated, and high precision manufacturing technology is required, it is difficult to be applied to manufacturing a large screen display device.

Therefore, in recent years, efforts have been made to simplify the manufacturing process and easily manufacture a large screen display by forming a surface type electron emission source using a carbon-based material having a low work function.

Graphite and carbon nanotubes (CNT) are well known as carbon-based materials suitable for the electron emission source. Among them, carbon nanotubes have a very small radius of curvature of about 100 μs, and thus 1 to 3 V / μm. It is expected to be an ideal electron emission source by smoothly generating electrons even at low electric fields.

As a method of forming an electron emission source using the aforementioned carbon-based material, there are screen printing and substrate growth. The screen printing method consists of screen printing a mixture of graphite or carbon nanotubes and an organic binder on a cathode electrode, followed by heat treatment to evaporate the organic binder. Substrate growth is performed by chemical vapor deposition on the cathode electrode. It is made by directly growing carbon nanotubes using chemical vapor deposition (CVD).

The screen printing method has a simple manufacturing process and can be easily applied to fabrication of a large screen display device. However, since the electron emission source formed by the screen printing method has a rough surface, electrons from the electron emission source are formed by forming an electric field. When released, the electron emission characteristics become nonuniform, which may lower the service life.

The substrate growth method has an advantage of excellent electron emission characteristics of an electron emission source by concentrating an electric field at the ends of carbon nanotubes by substantially vertically aligning individual carbon nanotubes on a cathode electrode. Compared with the screen printing method, the manufacturing process requires a higher precision and a deposition machine has a disadvantage in manufacturing a large screen display device.

Accordingly, an object of the present invention is to solve the above problems, and an object of the present invention is to make an electron emission source have a uniform surface so that electron emission characteristics are uniform, and a field emission display device which can be easily applied to fabrication of a large display device. The present invention provides a method for forming an electron emission source.

In order to achieve the above object, the present invention,

Forming a cathode on the substrate, sequentially laminating an adhesive layer, a carbon layer containing a photosensitive material, and a protective film on a transparent base film to form a carbon film, removing the protective film, and Stacking a carbon film on a substrate to contact the cathode electrode, placing an exposure mask on the carbon film and irradiating ultraviolet light to cure the carbon layer, and fixing the carbon layer on the cathode electrode, removing the base film and curing It provides a method for forming an electron emission source of a field emission display device comprising the step of removing the carbon layer is not heat and then heat treatment.

The forming of the carbon layer may include screen printing or spray coating of a mixture of graphite or carbon nanotubes, a vehicle, a filler, a frit, and a photosensitive material on the entire surface of the adhesive layer.

The composition for forming the carbon layer further includes an inorganic powder selected from the group consisting of alumina and zirconia, and a metal powder selected from the group consisting of silver (Ag), copper (Cu), and aluminum (Al).

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 to 5 are schematic diagrams at each detailed step for explaining a method for forming an electron emission source of a field emission display device according to a first embodiment of the present invention.

First, as shown in FIG. 1, cathode electrodes 2 are formed on a substrate 1. A carbon film obtained by filming a carbon material is produced to form an electron emission source on the cathode electrode 2.

In order to produce the carbon film, as shown in FIG. 2, a transparent base film 11 is prepared, an adhesive layer 12, a carbon layer 13 containing a photosensitive material on the base film 11, and The protective film 14 is sequentially laminated to complete the carbon film 10.

Since the base film 11 must transmit light to the carbon layer 13 in a subsequent exposure process, the base film 11 should have light transparency, for example, made of a material having a vinyl group. The carbon layer 13 is completed by screen printing or spray coating a composition containing graphite or carbon nanotubes, a vehicle, a filler, a frit, and a photosensitive material on the adhesive layer 12.

The vehicle included in the composition serves to adjust the viscosity and concentration of the composition so as to facilitate printing or application, and generally, all materials used in the paste composition may be used. For example, materials such as alpha-terpinol, ethyl cellulose, butyl carbitol acetate and the like can be used as the vehicle.

The composition may include inorganic powders such as glass frit, alumina, zirconia, and metal powders such as silver (Ag), copper (Cu), and aluminum (Al). The inorganic powder serves to fix the graphite or carbon nanotubes on the cathode as an adhesive material, and the metal powder serves to electrically connect the graphite or carbon nanotubes to the cathode as a conductive material.

After fabricating the carbon film 10 in this manner, the protective film 14 is removed, and the carbon film on the substrate 1 is brought into contact with the cathode electrode 2 as shown in FIG. 3. (10) is laminated. And as shown in FIG. 4, the exposure mask 20 is mounted on the carbon film 10, and ultraviolet-ray (dashed arrow) is irradiated to the carbon film 10. As shown in FIG.

The exposure mask 20 is formed with a hole 20a corresponding to a portion where an electron emission source is to be positioned on the cathode electrode 2, and the hole 20a of the exposure mask is irradiated from ultraviolet rays emitted from a light source (not shown). Only the ultraviolet rays passed through are irradiated to the carbon film 10. At this time, since the base film 11 is light-transparent, ultraviolet rays are transmitted to the carbon layer 13, and the portion of the carbon layer 13 irradiated with ultraviolet rays by the photosensitive material is selectively cured.

Next, the base film 11 is removed from the carbon layer 13, and the uncured carbon layer is removed using a developer (not shown) to cure on the cathode electrode 2 as shown in FIG. 5. Only the carbon layer 13 thus left is left. The carbon layer 13 is heat-treated to evaporate the vehicle contained in the carbon layer 13, and the metal powder is melted to complete the electron emission source.

6 to 8 are schematic diagrams at each detailed step for explaining an electron emission source forming method of a field emission display device according to a second embodiment of the present invention.

First, the cathode electrodes 2 are formed in a stripe pattern on the substrate 1 (see FIG. 1), and then a carbon film 40 is formed of a carbon material as shown in FIG. 6. In this embodiment, the carbon film 40 is characterized by having a patterned carbon layer 43, unlike the embodiment described above.

In order to fabricate the carbon film 40, a base film 41 is first prepared, an adhesive layer 42 is formed on the base film 41, and graphite or carbon nanotubes, a vehicle, a filler, and frit are mixed. Screen-printing the composition in a predetermined pattern to form a carbon layer 43, the protective film 44 is laminated on the carbon layer 43 to complete the carbon film 40.

The composition used to form the carbon layer 43 is made the same as in the above-described embodiment except that the photosensitive material is not included, and the pattern of the carbon layer 43 is to be formed on the cathode electrode 2. It is made the same as the pattern of the emission source.

After the carbon film 40 having the patterned carbon layer 43 is manufactured, the protective film 44 is removed, and the carbon layer 43 is formed of the cathode electrode 2 as shown in FIG. 7. The carbon film 40 is laminated on the substrate 1 to be in contact with the substrate 1. At this time, the roller 50 is moved onto the base film 41 to bring the carbon layer 43 on the cathode electrode 2. And the base film 41 is removed from the carbon layer 43, and the carbon layer 43 is left on the cathode electrode 2 as shown in FIG.

Finally, the carbon layer 43 is heat treated to evaporate the vehicle contained in the carbon layer 43, and the metal powder is melted to complete the electron emission source.

As described above, the method for forming an electron emission source according to the present invention produces a carbon film obtained by filming a carbon material without directly screen-printing the composition or growing carbon nanotubes on the cathode, and then forming the filmed carbon material. There is a great feature for transferring onto a cathode electrode.

Therefore, the present invention can form an electron emission source having a uniform surface by leaving the carbon layer on the cathode electrode and removing the base film, and fabricates a large screen display device by preparing a large amount of carbon film in advance and then applying the same to the display device fabrication. Not only is it advantageous, but also has the advantage of forming an electron emission source in a simplified process.

In addition, the electron emission source forming method provided by the present invention can be easily applied to the field emission display device of various configurations described below. 9 and 10 are respectively partially exploded perspective views of the field emission display device having the electron emission source completed by the above process.

First, cathode electrodes 2 are formed on the rear substrate 1 of the field emission display shown in FIG. 9, and an insulating layer 3 is formed on the front surface of the rear substrate 1 while covering the cathode electrodes 2. The gate electrodes 4 are formed on the insulating layer 3 in a stripe pattern perpendicular to the cathode electrode 2. In addition, a hole 5 penetrating the gate electrode 4 and the insulating layer 3 is formed at an intersection area between the cathode electrode 2 and the gate electrode 4, and the cathode electrode exposed by the hole 5 ( The electron emission source 6 is formed on 2).

In the rear substrate 1 'of the field emission display shown in FIG. 10, gate electrodes 4' are formed in a stripe pattern, and the front surface of the rear substrate 1 'is covered while covering the gate electrodes 4'. An insulating layer 3 'is formed on the cathode layer, and the cathode electrodes 2' are formed in a stripe pattern perpendicular to the gate electrode 4 'on the insulating layer 3', and the cathode electrode 2 'and the gate electrode are formed on the insulating layer 3'. An electron emission source 6 'is formed on one side edge of the cathode electrode 2' at the intersection region of 4 '.

In both of the field emission displays shown in FIGS. 9 and 10, a transparent anode electrode 8 is formed on the front substrate 7, and R (red), G (green), and B ( Blue) The fluorescent films 9R, 9B and 9G are positioned. Thus, when an electric field is formed around the electron emission sources 6 and 6 'by the voltage difference between the cathode electrodes 2 and 2' and the gate electrodes 4 and 4 ', electrons from the electron emission sources 6 and 6' are generated. Is emitted, and the emitted electrons are attracted to the high voltage applied to the anode electrode 8 and collide with the corresponding fluorescent film to emit the fluorescent film.

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 the range of.

As described above, according to the present invention, an electron emission source can be easily formed on a large screen display device having various configurations by transferring the filmed carbon material onto the cathode electrode. In addition, by leaving the carbon material on the cathode electrode and removing the base film, an electron emission source having a uniform surface is formed, and as a result, the field emission characteristics of the electron emission source can be made uniform.

Claims (9)

a) forming cathode electrodes on the substrate; b) sequentially laminating an adhesive layer, a carbon layer including a photosensitive material, and a protective film on the transparent base film to produce a carbon film; c) removing the protective film and laminating a carbon film on a substrate such that the carbon layer is in contact with the cathode electrode; d) fixing an carbon layer on the cathode by placing an exposure mask on the carbon film and irradiating ultraviolet light to cure the carbon layer; And e) removing the base film, removing the uncured carbon layer and then heat treatment Method for forming an electron emission source of the field emission display comprising a. The method of claim 1, The step of forming a carbon layer in step b), A method of forming an electron emission source for a field emission display device comprising screen printing or spray coating a mixture of graphite or carbon nanotubes, a vehicle, a filler, a frit, and a photosensitive material to the entire surface of the adhesive layer. The method of claim 2, The mixture is i) an inorganic powder selected from the group consisting of alumina and zirconia; And ii) a method for forming an electron emission source of a field emission display further comprising a metal powder selected from the group consisting of silver and copper; a) forming cathode electrodes on a substrate in a stripe pattern; b) sequentially laminating an adhesive layer, a carbon layer having a predetermined pattern, and a protective film on the base film to produce a carbon film; c) removing the protective film and laminating a carbon film on a substrate such that the carbon layer is in contact with the cathode electrode; d) adhering a carbon layer on the cathode by moving the roller over the base film; And e) removing the base film and heat treating the carbon layer Method for forming an electron emission source of the field emission display comprising a. The method of claim 4, wherein The step of forming a carbon layer in step b), A method of forming an electron emission source for a field emission display device comprising screen printing a mixture of graphite or carbon nanotubes, a vehicle, a filler, and a frit on a pressure-sensitive adhesive layer in a predetermined pattern. a) forming cathode electrodes on a substrate in a stripe pattern; b) sequentially laminating an adhesive layer, a carbon layer, and a protective film on the base film to produce a carbon film; c) removing the protective film and laminating a carbon film on a substrate such that the carbon layer is in contact with the cathode electrode; And d) removing the protective film to leave a carbon layer on the cathode electrode Method for forming an electron emission source of the field emission display comprising a. A base film; An adhesive layer formed on the base film; A carbon layer formed on the adhesive layer; And A protective film formed on the carbon layer to protect the carbon layer Carbon film for producing an electron emission source comprising a. The method of claim 7, wherein A carbon film for producing an electron emission source, wherein the base film is light transparency and the carbon layer contains a photosensitive material. The method of claim 7, wherein Carbon film for producing an electron emission source in which the carbon layer is formed in a predetermined pattern.

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