KR20010075970A - Field emission display device and method for making thereof - Google Patents

Abstract

PURPOSE: A field emission display device and a method of manufacturing the same are provided to improve a field emission property and to realize a display having a uniform brightness. CONSTITUTION: In a field emission display device, an upper substrate and an under substrate(2) are placed and sealed with a desired space. A cathode electrode(6) is installed on one of the substrates. An anode electrode is installed on one of the substrates to be crossed perpendicularly to the cathode substrate. A face type emitter(10) is manufactured with a carbon group of electron emission material to provide to a side surface of a cathode electrode in a pixel area. A desired shape of fine patterns which are etched with a laser ablation method are included in the respective pixel area. A phosphor is provided to the anode electrode to radiate by electrons emitted from the face type of emitter.

Description

Field emission display device and its manufacturing method {FIELD EMISSION DISPLAY DEVICE AND METHOD FOR MAKING THEREOF}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a field emission display device and a method for manufacturing the same. More particularly, the field emission display device having an emitter suitable for enlargement by improving electron emission characteristics and enabling display of uniform brightness, and its manufacture It is about a method.

In general, a field emission display device (FED) uses a quantum mechanical tunneling effect to emit electrons from an emitter provided to a cathode electrode, and impinges the emitted electrons on a phosphor coated anode electrode. It is a display element which implements an image.

Here, the emitter that emits electrons includes a spindt type emitter having a sharp tip and a surface type emitter.

The spin type emitter is manufactured by forming an insulating film and a gate electrode on one surface of a cathode electrode, etching the gate electrode and the insulating film, and stacking an electron emission material such as molybdenum or silicon into the etched space.

The spin type emitter is a structure that maximizes the local electric field by forming a very small radius of curvature of the tip portion of several hundred angstroms so that electron emission is smoothly performed.

However, since the spin type emitter is required to form an emitter tip in units of micrometers, it is difficult to form a uniform emitter as a whole, and the manufacturing cost is high, and it has disadvantages in large area.

Accordingly, a surface type emitter having a flat shape without a tip structure has been proposed by a simpler manufacturing method than a spin type emitter. As a material forming the surface type emitter, carbon fiber or carbon nano having good electron emission characteristics is proposed. There is a carbon-based material such as a tube, and as shown in Fig. 1, the surface type emitter 102 made of the material is provided on the surface of the electrode 104 in the same shape as the cathode electrode 104 (Fig. 1a) or only in the pixel region of the cathode electrode 104 (FIG. 1B).

Accordingly, when a predetermined voltage pattern is applied to the cathode electrode 104 and a line-shaped anode disposed vertically with the cathode electrode, the voltage difference applied to the cathode electrode and the anode electrode constituting each pixel is not applied. Accordingly, an electric field is formed to emit electrons from the emitter 102, and the emitted electrons collide with a fluorescent layer (not shown) of the anode to emit a fluorescent layer to implement a predetermined image.

However, the field emission display device having the surface type emitter of the above configuration has the following problems.

Cotton type emitters made of carbon fibers or carbon nanotubes are usually powdered by cutting and crushing carbon fibers (or carbon nanotubes), and then additives such as frit and binder are added to the powder to prepare emitter pastes. This is produced by forming a film on one surface of the cathode by thick film technology (printing, slurry, electrodeposition, etc.), so that individual carbon fibers or carbon nanotubes inside the emitter are not aligned vertically from the cathode toward the anode. However, there is a disadvantage in that the electron emission characteristics as the emitter are degraded because they are positioned horizontally or inclined at a predetermined angle.

As described above, when the emitter is formed by using a thick film technology, the number of carbon fibers or carbon nanotubes protruding from the surface of the emitter is not the same in each pixel region, so that different amounts of electrons are generated in the pixel region. Is released.

Therefore, the luminance of each pixel is not uniform during operation of the device, which causes partial unevenness, which limits the size of the device.

Accordingly, an object of the present invention is to provide a field emission display device having an emitter which can improve electron emission characteristics, can display a uniform brightness, and has an emitter suitable for large size.

Another object of the present invention is to provide a method of manufacturing a field emission display device which can effectively manufacture the above-described field emission display device.

1 is a perspective view showing a state in which an emitter according to the prior art is provided to a cathode electrode;

2 is a cross-sectional view of a field emission display device according to the present invention;

3 is a perspective view showing a state where an emitter of the present invention is provided to a cathode electrode;

4 is a cross-sectional view showing a portion corresponding to one pixel region in the field emission display device of the present invention.

5 is a process flowchart sequentially illustrating a method of manufacturing a field emission display device according to the present invention.

The present invention to achieve the above object,

Upper and lower substrates sealed at predetermined intervals;

A cathode electrode provided on one of the substrates;

An anode electrode provided on the other one of the substrates so as to vertically intersect the cathode electrode;

A plane type emitter made of a carbon-based electron emission material and provided on one surface of the cathode electrode of the pixel region, wherein a fine pattern having a predetermined shape etched by laser ablation is provided in each pixel region;

A phosphor provided to the anode to emit light by electrons emitted from the surface type emitter;

It provides a field emission display device comprising a.

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

An electrode forming step of forming a conductive film on one surface of the upper substrate and the lower substrate to form a cathode electrode and an anode electrode, respectively;

Forming a fluorescent film by applying a phosphor to one surface of the anode electrode;

An emitter paste manufacturing step of preparing an emitter paste by mixing a carbon-based electron-emitting material and an additive;

A thick film printing step of screen printing the emitter paste on the surface of the cathode electrode;

A drying step of drying the emitter paste;

Forming a fine pattern of a predetermined shape in each pixel region by etching the dried emitter paste by laser ablation;

Firing the emitter paste;

A sealing step of integrally sealing the upper substrate and the lower substrate;

It provides a method for manufacturing a field emission display device comprising a.

Thus, according to the present invention in which the fine pattern is formed in the pixel region of the emitter by laser ablation, the sharp tip of the electron emitting material is exposed on the etching surface of the fine pattern, so that the amount of the electron emitting material used for the electron emission. It can be significantly increased compared to the prior art.

Therefore, the entire screen formed by each pixel can be displayed with uniform brightness, which makes it possible to increase the size of the device.

Hereinafter, a field emission display device and a method of manufacturing the same according to exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view of the field emission display device according to the present invention, in which the field emission display device has a predetermined line on the lower substrate 2 and the upper substrate 4 and the lower substrate 2 disposed to face each other at a predetermined interval. A cathode electrode 6 arranged in a shape and an anode electrode 8 arranged in a line shape on the upper substrate 4 so as to perpendicularly intersect the pattern of the cathode electrode 6.

In addition, an emitter 10 including an electron emission material such as carbon nanotubes is positioned on the cathode electrode 6, and a fluorescent film 12 is formed on one surface of the anode electrode 8 facing the emitter 10. This is located.

In the field emission display device having such a structure, the emitter 10 is provided on the surface of the electrode 6 in the same shape as the cathode electrode 6, as shown in FIG. 3 (FIG. 3A), or It is provided only in the pixel region of the cathode electrode 6, that is, the region where the cathode electrode 6 and the anode electrode 8 intersect (FIG. 3B), and the emitter 10 has a lattice pattern as shown in FIG. 3A. Fine pattern 14 is provided, or as shown in FIG. 3B, a fine pattern 14 'is formed by a stripe pattern, and the fine pattern 14 or 14' is laser ablation, which is one of optical etching methods. It is formed by the (ablation) method.

Here, the shape of the fine pattern is not limited, and the fine pattern preferably has a width of about 20 μm, which is similar to the distance between the cathode electrode and the anode electrode.

Next, the manufacturing method of the field emission display element by this invention is demonstrated.

FIG. 5 is a process flowchart sequentially illustrating a method of manufacturing a field emission display device according to the present invention. As shown in FIG. 5, the method of manufacturing a field emission display device includes a cathode electrode formed on one surface of an upper substrate and a lower substrate. An anode electrode was formed, a phosphor was coated on one surface of the anode electrode to form a fluorescent film, and then an emitter paste was prepared by mixing a carbon-based electron emission material and an additive, and the emitter paste was applied to the surface of the cathode electrode. After screen printing, the printed emitter paste is dried, the dried emitter paste is etched by laser ablation to form a fine pattern of a predetermined shape in each pixel region, and then the emitter paste is fired. The process of integrally sealing the upper substrate and the lower substrate.

A method of manufacturing the field emission display device as described above will be described below with reference to FIGS. 2 and 5.

In order to fabricate the field emission display device, first, indium tin oxide is sputtered on one surface of the upper substrate 4 made of transparent glass, and then etched to form the line-shaped anode electrode 8.

The phosphor is screen printed on the surface of the anode electrode 8 in a predetermined shape and heat-treated to form a phosphor film 12. Subsequently, the paste for spacer 16 is printed in parallel between the phosphors and heat-treated.

Another surface of the lower substrate 2, which is made of transparent glass, is sputtered or screen printed on indium tin oxide or silver to form a cathode electrode 6 having a line shape. Then, the paste for spacer 18 is printed and heat-treated between the cathode electrodes 6 using the screen printing method.

Subsequently, the carbon nanotubes, which are electron-emitting materials, are cut and crushed to a certain size, and powdered, and additives such as frit and a binder are mixed with the powder to prepare an emitter paste having a specific viscosity. Is printed on one surface of the cathode electrode 6.

At this time, the paste printing is performed by a thick film process including a conventional screen printing method. The screen printing of the emitter paste fixes the substrate and the screen mesh to the screen printing machine, and the squeeze is used to fix the emitter paste to the cathode electrode. It consists of printing on the surface.

After the printed emitter paste is dried, the emitter paste is etched by laser ablation to form a stripe pattern or a lattice-like fine pattern in the entire emitter paste or in each pixel region.

Here, the laser ablation method focuses on a desired etching portion and then irradiates a laser beam, the energy of the laser beam is absorbed by the material to be etched, and the material of the minute region that absorbs the large energy instantaneously is converted into a desired portion. As one of the dry etching techniques in which the etching is performed, the etching area is determined by the diameter of the laser beam.

The fine pattern forming operation described above may be performed while the substrate is placed on a processing table capable of transferring the substrate and the substrate is transported in the biaxial direction (front, rear, left and right directions on the processing table), and the substrate is fixed. The laser ablation unit may be transported.

Here, the composition ratio of the emitter paste is composed of 0.5 to 0.8 glass powder, 0.5 to 0.8 silver and 2 to 20 binder when the surface electron source material is 1; Preferably, the surface electron source material preferably includes carbon nanotubes (CNT) or carbon fibers, because the energy of the laser beam when the laser beam is irradiated to the etching portion to form a fine pattern This is because the additives of the received portion evaporate to protrude carbon nanotubes (CNTs) or carbon fibers from the surface of the emitter 10 as shown in the cross-sectional view of FIG. 4 to maximize the electron emission effect.

In addition, a laser having a wavelength of 532 to 1064 nm may be used for the laser ablation.

FIG. 4 illustrates one unit pixel 10 which is cut by laser ablation and provided with a plurality of sub-pixels 10 '.

After forming the fine pattern using the laser beam in this way, after firing the emitter paste, the seal frit except for the portion to be an exhaust port at the edge of the upper substrate 4 and the lower substrate 2 Apply (20). At this time, the upper substrate 4 and the lower substrate 2 are arranged so that the line-shaped anode electrode 8 and the cathode electrode 6 cross each other perpendicularly, and are sealed by heat treatment while applying an appropriate pressure.

Then, a vacuum pump is connected to the exhaust port to form the inside of the substrate in a vacuum of 10 ⁻³ to 10 ⁻¹⁰ Torr, and then seal the exhaust port.

As a result, a field emission display device having improved electron emission characteristics may be manufactured by exposing a sharp tip of an electron emission material to a surface of a light-etched fine pattern.

In the above, the present invention is applied to a field emission display device having a bipolar tube structure, but the present invention is not limited thereto, and the present invention can also be applied to a display device having a triode structure, and the claims and the detailed description of the invention and the accompanying drawings. Various modifications can be made within the scope and it is obvious that this also falls within the scope of the present invention.

As described above, according to the present invention, since the sharp tip of the electron-emitting material is exposed on the etching surface of the fine pattern, the amount of the electron-emitting material used for electron emission can be significantly increased as compared with the related art.

Therefore, the device can be driven even at a lower voltage than in the related art.

In addition, since a plurality of fine patterns are formed in one pixel, the entire screen formed by these pixels is displayed with uniform luminance, thereby enabling the device to be enlarged.

Claims (8)

Upper and lower substrates sealed at predetermined intervals; A cathode electrode provided on one of the substrates; An anode electrode provided on the other one of the substrates so as to vertically intersect the cathode electrode; A plane type emitter made of a carbon-based electron emission material and provided on one surface of the cathode electrode of the pixel region, wherein a fine pattern having a predetermined shape etched by laser ablation is provided in each pixel region; A phosphor provided to the anode to emit light by electrons emitted from the surface type emitter; Field emission display device comprising a. The field emission display device of claim 1, wherein the surface type emitter is provided only in a portion where the cathode electrode is provided. The field emission display device of claim 1 or 2, wherein the carbon-based electron emission material is formed of any one selected from carbon fiber and carbon nanotubes. The field emission display device of claim 3, wherein the fine pattern comprises a stripe pattern. The field emission display device of claim 3, wherein the fine pattern comprises a lattice pattern. The field emission display device of claim 3, wherein the fine pattern has a width of about 20 μm. An electrode forming step of forming a conductive film on one surface of the upper substrate and the lower substrate to form a cathode electrode and an anode electrode, respectively; Forming a fluorescent film by applying a phosphor to one surface of the anode electrode; An emitter paste manufacturing step of preparing an emitter paste by mixing a carbon-based electron-emitting material and an additive; A thick film printing step of screen printing the emitter paste on the surface of the cathode electrode; A drying step of drying the emitter paste; Forming a fine pattern of a predetermined shape in each pixel region by etching the dried emitter paste by laser ablation; Firing the emitter paste; A sealing step of integrally sealing the upper substrate and the lower substrate; Method of manufacturing a field emission display device comprising a. The method of manufacturing a field emission display device according to claim 7, wherein the laser used in the laser ablation method has a wavelength band of 532 to 1064 nm.