KR100406817B1 - Manufacturing method of field emission display device - Google Patents

Abstract

Provided is a method of manufacturing a field emission display device capable of forming a carbon emitter more precisely on a cathode without causing a short between the cathode and the gate electrode.

The method of manufacturing the field emission display device includes forming an anode electrode and a fluorescent film on one surface of a first substrate; Forming a cathode of a stripe pattern on one surface of the second substrate; Forming an insulating layer on the entire surface of the second substrate above the cathode electrode and patterning the insulating layer to selectively expose the emitter forming portion of the cathode electrode; Forming a carbon emitter on an emitter forming portion of the cathode by electrophoresis; After forming the carbon emitter, forming a gate electrode having a stripe pattern perpendicular to the cathode electrode on the insulating layer; Integrally sealing the first and second substrates.

Description

Manufacturing Method of Field Emission Display Device {MANUFACTURING METHOD OF FIELD EMISSION DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a field emission display device, and more particularly, to manufacturing a field emission display device in which a carbon emitter can be more precisely attached to a cathode electrode while suppressing a short circuit between the cathode electrode and the gate electrode. It is about a method.

Recently, the use of carbon materials as the electron emission source of the field emission display device has been actively studied. Among these, carbon nanotubes have a very fine radius of about 100 kV at the end, so that an external voltage of 10 to 50 V It is known that electron emission occurs smoothly, and is expected to be an ideal electron emission source.

The carbon material is applied to the emitter as a structure in which a cathode electrode and an anode electrode are formed on a pair of substrates and a carbon material is laminated on the cathode electrode, but this structure can apply a high voltage to the anode electrode. There is a limitation that the brightness of the screen is not enough, and the emitter current can not accurately control the emission current, it is difficult to implement a video or multi-tone color image.

In addition, a triode structure is proposed in which a gate electrode is formed on the cathode electrode to control the emitter emission current by the voltage difference between the two electrodes. There is a disadvantage of connecting the electrodes to cause frequent short generation between the two electrodes.

As a result, various methods for attaching a carbon material on a cathode electrode have been proposed, and US Patent No. 6,116,975 discloses a substrate in which a cathode electrode and a gate electrode are formed in an electrodeposition liquid in which a carbon material is dispersed, and uses electrophoresis on the cathode electrode. A process for attaching carbon material is disclosed.

However, the method also requires a new manufacturing method to prevent the carbon material is distributed between the cathode electrode and the gate electrode in the electrophoretic process, and short the two electrodes.

Accordingly, an object of the present invention is to solve the above problems, and an object of the present invention is to provide a field emission display device capable of more precisely forming a carbon emitter on a cathode without causing a short between the cathode and the gate electrode. It is to provide a manufacturing method.

1 is a partially cutaway perspective view of a field emission display device;

2 to 10 are schematic views at each step for explaining a method for manufacturing a field emission display device according to the present invention.

11 and 12 are SEM photographs showing the results of electrodeposition of the carbon emitter.

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

Forming an anode electrode and a fluorescent film on one surface of the first substrate; Forming a cathode of a stripe pattern on one surface of the second substrate; Forming an insulating layer on the entire surface of the second substrate above the cathode electrode and patterning the insulating layer to selectively expose the emitter forming portion of the cathode electrode; Forming a carbon emitter on an emitter forming portion of the cathode by electrophoresis; Forming a stripe pattern gate electrode vertically crossing the cathode electrode on the insulating layer; Provided is a method of manufacturing a field emission display device comprising integrally sealing the first and second substrates.

As described above, since the carbon emitter is formed before the gate electrode, the present invention effectively suppresses the occurrence of a short between the cathode electrode and the gate electrode, and the electrophoresis method can selectively deposit the carbon material even in the fine holes having a diameter of 40 μm or less. Therefore, it has an advantage in implementing a fine pattern.

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

First, as shown in FIG. 1, the field emission display device forms the anode electrode 4 and the fluorescent films 6R, 6G, and 6B on the first substrate 2. And a cathode electrode 10, a gate electrode 12, and a carbon emitter 14 are formed on the second substrate 8, and the first and second substrates 2, 8 are integrally formed while the interior thereof is high vacuum. It consists of a sealed structure.

In more detail, the anode electrode 4 receives a high voltage required for electron acceleration and draws electrons to the fluorescent film 6, and the anode electrode transmits light emitted from the fluorescent film 6. (4) and the first substrate 2 each consist of a transparent indium tin oxide (ITO) film and a transparent glass plate.

The cathode electrode 10 and the gate electrode 12 are formed in a stripe pattern perpendicularly intersecting with each other so that their intersection regions constitute one pixel, and an insulating layer 16 is positioned therebetween so that the two electrodes are disposed. Insulate. And a carbon emi made of carbon nanotubes, graphite, diamond powder, diamond-like carbon, or a mixture thereof in the space where the gate electrode 12 and the insulating layer 16 are removed on the cathode electrode 10, that is, inside the emitter formation site. The rotor 14 is located in the face type.

According to the above structure, when a pulse signal necessary for driving a pixel is applied to the cathode electrode 10 and the gate electrode 12, electrons are emitted from the carbon emitter 14 by forming an electric field due to the voltage difference between the two electrodes, The emitted electrons are attracted by the high voltage of the anode electrode 4 and collide with the corresponding fluorescent film 6 to excite them to implement a predetermined screen.

Next, the method of manufacturing the field emission display device described above will be described in detail with reference to FIGS. 2 to 10.

First, a transparent first substrate 2 is prepared, an ITO film is deposited on the surface thereof, and an anode electrode 4 is formed, and each R, G, B phosphor paste is printed on the surface of the anode electrode 4 and then fired. The fluorescent films 6R, 6G and 6B are formed. (See Figure 2)

In addition, silver (Ag) paste is screen-printed on the surface of the second substrate 8 in a stripe pattern, and then fired for several hours in a furnace at 200 to 700 ° C. to form the cathode electrode 10, and the cathode electrode 10. The glass paste containing silicon oxide (SiOx) is screen-printed several times on the entire surface of the second substrate 8 and then fired to form an insulating layer 16 having a predetermined thickness. (See Figure 3)

The insulating layer 16 is then patterned to selectively expose the emitter formation site of the cathode electrode 10.

To this end, a photoresist film 18 is formed by applying a photoresist solution on the insulating layer 16 and then thermally treating the photoresist film 18. A photoresist film is selectively exposed using an exposure mask (not shown) and then developed to develop a plurality of holes 18a. ). The insulating layer 16 is etched in an acid to form openings 16a having a diameter of 30 to 80 µm corresponding to the emitter formation sites, and the remaining photoresist film 18 is removed. (See Figs. 4A to 4B)

Next, the electrodeposited carbon material is formed on the emitter forming portion of the cathode electrode 10 by using an electrophoresis method, first, an electrodeposition liquid required for this process is prepared.

The electrodeposition liquid is a carbon material and a charging agent (mixing and dispersing) in a solvent so that the carbon material in the solution to have a positive or negative charge, wherein the carbon material is graphite, diamond powder, diamond-like carbon, carbon nanotubes Or mixtures thereof.

More specifically, the electrodeposition liquid is dissolved by mixing La-nitrate and Mg-nitrate as a charging agent in pure water, and then diluting the solution with isopropyl alcohol. At this time, the mixing ratio of pure water, La-nitrate, Mg-nitrate and isopropyl alcohol is 30 to 80: 1 to 10: 1 to 10: 800 to 1500 weight ratio. Then, glycerol serving as a binder is added to the solution, followed by stirring. The graphite or carbon nanotubes are added thereto, and the mixture is sufficiently stirred for 2 hours or more to prepare. At this time, the mixing ratio of glycerol and graphite or carbon nanotubes is 500 to 100: 1 to 10 by weight.

In the electrodeposition liquid prepared as described above, since graphite has a positive charge, a negative voltage is applied to the cathode electrode to electrodeposit the graphite dispersed in the electrodeposition liquid onto the cathode, as shown in FIG. 5 as an example of the electrophoretic process. The electrodeposition liquid is poured into the container 20, and the second substrate 8 and the electrode plate 22 having the cathode electrode 10 are fixed to the inside of the container 20 by using fixing means (not shown).

Here, the second substrate 8 is fixed so that the cathode electrode 10 faces the bottom of the container 20 to prevent the adhesion of graphite particles by precipitation, the electrode plate 22 is the cathode electrode 10 By forming a constant electric field around the graphite particles are uniformly attached to the surface of the cathode electrode (10).

As a result, the graphite particles in the electrodeposition liquid were more uniformly stirred for several hours, and a direct current power source connected to the cathode electrode 10 and the electrode plate 22 was operated to achieve 10-400 V and 5 to 100 mA electrodeposition conditions. When electrodeposition is carried out for a few seconds to several minutes, graphite particles dispersed in the electrodeposition liquid are selectively attached to the emitter formation portion of the cathode electrode 10 to form a carbon emitter 14 having a predetermined thickness. (See Figure 6)

The second substrate 8 having the carbon emitter 14 formed thereon is fired for several hours in a furnace at 200 to 700 ° C. to fix the frit component of the carbon emitter 14, and then the gate to the second substrate 8. Form an electrode.

Since only the cathode electrode 10 and the insulating layer 16 are formed on the second substrate 8 during the electrophoresis process before the gate electrode is formed, a carbon material is formed on the emitter forming portion of the cathode electrode 10. It has the advantage of being able to attach more precisely.

Next, a gate electrode is manufactured using a thick film or a thin film process.

First, the thick film process will be described. The silver paste is screen printed in a stripe pattern perpendicular to the cathode electrode 10 using a screen mesh (not shown) in which the same pattern as the carbon emitter 14 is formed. The second substrate 8 is fired in a furnace of 200 to 700 ° C. to fix the paste to form the gate electrode 12. (See Figure 7)

The gate electrode 12 manufactured as described above is formed in a stripe pattern perpendicular to the cathode electrode 10 on the surface of the insulating layer 16 except for the carbon emitter 14 by the pattern of the screen mesh. As an embodiment, after the carbon emitter 14 is formed, a photoresist film is formed on the insulating layer, and the photoresist film is partially exposed and developed to selectively form the protective layer 24 only on the carbon emitter 14. (See Figure 8)

Then, the photosensitive silver paste is printed on the entire surface of the insulating layer 16 and selectively exposed and developed only a portion corresponding to the gap between the upper portion of the protective layer 24 and each gate electrode line to form the gate electrode 12 line. do. (See Fig. 9) Subsequently, the protective layer 24 on the carbon emitter 14 is removed, washed with a weak nitric acid solution, and then fired in a 200-700 ° C. atmosphere to fix the gate electrode 12.

In the thin film process, as described above, the protective layer 24 is selectively formed only on the carbon emitter 14, and then an aluminum thin film having a thickness of 1000 to 5000 Å is deposited on the entire surface of the insulating layer 16 using an evaporator. A portion of the aluminum thin film is selectively removed using a known photolithography process to form a gate electrode 12 line as shown in FIG. 7.

The first and second substrates 2 and 8 completed as described above are provided and integrally assembled so that the multilayer films formed on these substrates face each other, and the interior of the field emission display device is completed by exhausting the interior using an exhaust device (not shown). do. (See Figure 10)

FIG. 11 is an SEM photograph of a second substrate on which a carbon emitter is electrodeposited by the above-mentioned electrophoresis method, and shows a step before forming a gate electrode. It is seen that the carbon emitter is black in the photograph, and the carbon emitter is densely deposited in an elaborate pattern on the emitter formation site where the insulating layer on the cathode electrode is removed.

On the other hand, FIG. 12 is a SEM photograph of a substrate on which both a cathode electrode and a gate electrode are formed according to the prior art, and then the carbon emitter is electrodeposited by electrophoresis, which is white in the photograph. Here, the carbon emitter is not precisely electrodeposited on the emitter forming site, it can be seen that a considerable number of carbon materials are electrodeposited to the gate electrode surface.

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, the carbon emitter can be precisely attached to the cathode electrode in a more precise pattern by forming the cathode electrode and the insulating layer and electrodepositing the carbon emitter by electrophoresis. Formation has an advantage of fundamentally suppressing occurrence of short between the cathode electrode and the gate electrode due to the carbon emitter.

Claims (10)

Forming an anode electrode and a fluorescent film on one surface of the first substrate; Forming a cathode of a stripe pattern on one surface of the second substrate; Forming an insulating layer on the entire surface of the second substrate above the cathode electrode and patterning the insulating layer to selectively expose the emitter forming portion of the cathode electrode; Forming a carbon emitter on an emitter forming portion of the cathode by electrophoresis; After forming the carbon emitter, forming a gate electrode having a stripe pattern perpendicular to the cathode electrode on the insulating layer; And integrally sealing the first and second substrates. The method of claim 1, And forming the cathode electrode by screen printing, firing, and solidifying the silver paste. The method of claim 1, And forming the insulating layer by screen printing a glass paste several times, firing the glass paste, and then patterning the same by a photolithography process. The method of claim 1, Forming the carbon emitter, Dispersing the carbon material and the charging agent in a solvent to prepare an electrodeposition liquid in which the carbon material has a predetermined charge; Dipping the second substrate on which the cathode electrode and the insulating layer are formed in an electrodeposition liquid; And attaching the carbon material to the cathode electrode by an electrostatic force by applying a voltage having a polarity opposite to that of the charge of the carbon material to the cathode electrode. The method of claim 4, wherein And the electrodeposition liquid comprises a carbon material, La-nitrate and Mg-nitrate as charging agents, pure and isopropyl alcohol as solvents, and glycerol as a binder. The method of claim 5, A method of manufacturing a field emission display device in which the carbon material is made of graphite, diamond powder, diamond-like carbon, carbon nanotubes, or a mixture thereof. The method of claim 4, wherein And fixing the cathode electrode so as to face the bottom of the container in which the electrodeposition liquid is contained, and disposing an electrode plate parallel to the second substrate between the cathode electrode and the bottom of the container. The method of claim 1, Forming the gate electrode, A method of manufacturing a field emission display device comprising screen printing a silver paste in a stripe pattern perpendicular to a cathode using a screen mesh having a pattern identical to that of a carbon emitter. The method of claim 1, Forming the gate electrode, Forming a protective layer over the carbon emitter; Printing photosensitive silver paste over the insulating layer; Selectively exposing and developing only a portion corresponding to a distance between the upper portion of the protective layer and each gate electrode line; A method of manufacturing a field emission display device comprising removing the protective layer. The method of claim 1, Forming the gate electrode, Forming a protective layer over the carbon emitter; Depositing an aluminum thin film on the entire surface of the insulating layer using an evaporation apparatus; Patterning the aluminum thin film by a photolithography process; A method of manufacturing a field emission display device comprising removing the protective layer.