KR20100080268A

KR20100080268A - Field emission cathode plate using fine-porous carrier and field emission display by the same

Info

Publication number: KR20100080268A
Application number: KR1020090004093A
Authority: KR
Inventors: 안승태
Original assignee: 안승태
Priority date: 2008-12-29
Filing date: 2009-01-19
Publication date: 2010-07-08

Abstract

PURPOSE: A field emission cathode plate using a fine-porous carrier and a field emission display by the same are provided to be thermally and electrically stabilized by limiting an electron emitter in the carrier. CONSTITUTION: A fine-porous carrier includes fine pores. An electron emitter(20) fills the fine pores. A cathode electrode(10) is arranged on one side of the electron emitter and is electrically connected with the electron emitter. The fine-porous carrier is arranged in the cathode electrode. An adjusting layer(12) is interposed between the electron emitter and the cathode electrode.

Description

Field emission cathode plate using fine-porous body and field emission display thereby {field emission cathode plate using fine-porous carrier and field emission display by the same}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a field emission cathode plate and a field emission display thereby, and more particularly to a cathode plate for field emission using a microporous body having a porosity and a field emission display thereby.

Field emission refers to the emission of electrons in a vacuum even at room temperature when electrons pass through an energy barrier near the surface of a metal or semiconductor by an electron tunnel effect when an electric field of a threshold value or more is applied to a metal or semiconductor placed in a vacuum. Cathode plates, which are electron emission sources, can be largely classified into tip-type and flat-type, and carbon nanotube (CNT) -type electron emission sources can be manufactured in both tip and flat types. Do.

In the case of the tip type, it can be classified into a metal tip and a silicon tip according to the type of emitter material forming the tip. Metal tips mainly use molybdenum (Mo) and have the advantage of obtaining a high current density, but the stability and reliability of the tip and the manufacturing process is difficult, such as not yet commercially available.

The silicon tip is fabricated using isotropic etching of a silicon substrate by a plasma etching method using SF ₆ gas. Such a silicon tip has the advantages of easy structure control, uniformity, and compatibility with semiconductor processes. The emission current is unstable, there is a high risk of tip breakage, and there is a limitation in utilizing the surface oxide film.

In the case of the planar type, carbon-based thin films such as diamond, DLC (Diamond-Like Carbon), graphite, and the like, Surface Conduction Emitter (SCE), Metal-Insulator-Metal (MIM) or Metal- Insulator-Semiconductor). Recently, the utilization of carbon nanotube structures as carbon-based electron emission sources has been actively investigated.

By the way, the carbon-based thin film has the advantages of easy large area, low work function, stable physical-chemically, and high thermal conductivity, but the emission area is not clearly defined, and the uniformity is not good. SCE has a low price and a large size, but has a disadvantage in that the ratio of electrons arriving at the anode is very low compared to the surface current. MIM is resistant to external contamination because it emits electrons inside the insulating layer, but has a low field emission current and poor thermal stability.

Carbon nanotubes are electron emission sources that can take advantage of the tip type and planar type because electrons are concentrated at the sharp end of the nanotubes to facilitate electron emission and have some characteristics of diamond-related materials. However, the formation of carbon nanotubes depends on the printing method, and there are many problems to be solved such as preventing the agglomeration of carbon nanotubes and straightening the carbon nanotubes.

Therefore, the technical problem to be achieved by the present invention is to provide a field emission cathode plate using a microporous body that can implement a high current density, stable emission current, thermally and structurally stable. Another object of the present invention is to provide a field emission display using the cathode plate.

The cathode plate of the present invention for overcoming the above technical problem includes a micropore body including micropores and an insulator, an electron emitter filled in the micropores, and one side of the electron emitter and electrically connected to the electron emitter. And a cathode electrode on which the microporous body is placed.

In the cathode plate of the present invention, the microporous body may be any one selected from inorganic oxide pore bodies or two or more kinds of compound pore bodies. In addition, in the preferred cathode plate of the present invention, the electron emitter may be a tip type or a planar type, the electron emitter may be any one selected from a metal material, a semiconductor material and a carbon-based material or a combination thereof. In this case, the carbon-based material is preferably carbon nanotubes, one or more carbon nanotubes may be located in the pores.

In the cathode plate, a control layer made of the same material or different materials as the cathode electrode may be further provided between the electron emitter and the cathode electrode, and the control layer may be formed through an open space between the microporous bodies. It can also be combined with each other.

Furthermore, in the cathode plate of the present invention, the microporous body may be provided in plurality, and the microporous body may further include a support such that each microporous body is disposed separately from each other, and the support is the semiconductor. It may be any one selected from a material, a carbon-based material and a metal material or a combination thereof. In addition, the support may include a separate pore having a pore of a different size from the micropore, and the surface exposed to the outside in the separate pore may be coated with a material for a getter.

Field emission display using the cathode plate of the present invention for overcoming the other technical problem and the anode panel and the cathode panel disposed to face each other at a constant interval, and to maintain the gap between the two panels to seal the inside with a vacuum A spacer and an anode electrode and a cathode plate disposed on opposite surfaces of the two panels, respectively. In this case, the cathode plate includes micropores and is an insulator microporous body, an electron emitter filled in the micropores and one side of the electron emitter is electrically connected to the electron emitter, the microporous body is It includes a cathode electrode to be placed.

According to the field emission cathode plate and the field emission display using the microporous body of the present invention, by restricting the electron emitter in the pores, the current emitted from the electron emitter is stabilized, and thermal, structural and electrical It is possible to provide a stable cathode plate and display. In particular, in the case of the carbon nanotube structure, by filling it in the pores can solve the conventional problem that the carbon nanotubes are not cohesive or aligned with each other.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art.

Hereinafter, a field emission cathode plate which can stably emit an electric field and can be used for a long time using the features of the microporous body is presented. In addition, by applying the cathode plate to the field emission display, which has recently been spotlighted as a display element, a solution to the problem of the cathode plate of the conventional field emission display. According to the International Union of Pure and Applied Chemistry (IUPAC), nanopore means a porous material having a pore size between 0 and 1000 nm, and again, depending on the pore size, 2 nm), mesoporous body (2-50 nm), and macroporous body (> 50 nm).

Nanoporous body can be variously applied in the scope of the present invention. The pore body includes an inorganic oxide, carbon, single element and two kinds of compounds. Inorganic oxide pores include alumina, silica, titania, zirconia, zeolite, and the like. Carbon pores are activated carbon and meso carbon materials, and mono-small pores are mainly made of metal such as meso silicon, In addition, the two or more kinds of compound pores include phosphate compounds such as AlPO ₄ , sulfide compounds, nitride compounds, and the like. The nanoporous body to be applied to the present invention is a microporous body (0-2 nm) defined above, for example, a zeolite or a phosphate compound may be used.

The cathode plate of the present invention comprises an electron-emitting body emitting electrons by the field emission principle and a microporous body supporting the electron-emitting body. In the following examples, only the microporous zeolite will be described for convenience of description. Of course, even if the size of the zeolite and its structure and pores are different, the cathode plate can be applied to other microporous bodies within the scope of the present invention. Accordingly, the zeolite is defined as a material representing the microporous body of the present invention, and the concept of the present invention can be seen to be applied to other microporous bodies.

1 is a perspective view showing a first cathode plate 100 which is one example of a cathode plate of the present invention.

Referring to FIG. 1, the microporous body 30 is bonded onto the cathode electrode 10, and the electron emitting body 20 is filled in the pores 22 of the microporous body 30. The electron-emitting body 20 is electrically connected to the cathode electrode 10 on one side and exposed to the outside of the microporous body 30 on the other side. At this time, each electron-emitting body 20 is electrically insulated by the microporous body 30.

The cathode electrode 10 includes metals such as tungsten (W), niobium (Nb), tantalum (Ta), molybdenum (Mo), chromium (Cr), aluminum (Al), and copper (Cu), and these metal elements. there can be mentioned an alloy or compound (e.g., nitride, or _{WSi 2, MoSi 2, TiSi 2} , TaSi 2 , etc. of the silicide of the tiN and the like), a silicon semiconductor, or ITO (indium tin oxide), such as (Si). The cathode electrode 10 may be formed by an electron beam deposition method, a deposition method such as a hot filament deposition method, a sputtering method, a combination of a CVD method, an ion plating method, an etching method, a screen printing method, a plating method, a lift-off method, or the like.

The microporous body 30 provides a space in which the electron-emitting body 20 is supported. The microporous body 30 may vary the size of the material and the pores, depending on the conditions under which the first cathode plate 100 is used. For example, considering the radius of the pores, the spacing between the pores, the height (h) of the microporous body, the size of the electric field applied to the electron-emitting body 20, the use of the first cathode plate 100, etc. Electrical insulation of the microporous body 30 may be different.

The electron emitter 20 may be any material that emits electrons by the field emission effect. Specifically, a metal material such as molybdenum (Mo), a semiconductor material such as silicon (Si), or a carbon-based material may be used as the electron emitter 20. A portion of the electron emitter 20 exposed to the outside of the microporous body 20 may be flat, or may be manufactured as a tip. In the figure, the exposed portion is a planar electron emitter 20 is represented.

The tip-type electron emitter 20 may mainly be a metal material and a semiconductor material. For example, the electron-emitting body 20 of the metal material may make a portion exposed to the outside of the microporous body 30 to a pointed shape by an electrochemical etching method. The electron-emitting body 20 of the semiconductor material may be manufactured in a tip shape by combining a photolithography process, a lift-off method, a plasma etching method, or the like. The tip-shaped portion of the electron-emitting body 20 may be located in the pores 22 or may protrude out of the pores 22 partially or entirely.

The carbon-based thin film may be diamond, diamond-like carbon (DLC, graphite, etc.) In particular, the carbon-based thin film can utilize the carbon nanotube structure. Is concentrated, so it is easy to emit electrons and has some characteristics of diamond-related materials, so it can take advantage of the tip type and the planar type.

The carbon nanotube structure consists of carbon nanotubes, carbon nanofibers, or a combination thereof. The structure may contain a magnetic material (eg, iron, cobalt, or nickel) or a magnetic material layer may be formed on the surface thereof. The carbon nanotube structure may be in the form of a powder, a thin film or an auger. The structure may be filled in the pores 22 using a binder, in particular a conductive binder, or grown directly on the cathode electrode 10.

The carbon nanotube structure is formed by a variety of vapor deposition methods such as known PV discharge method or laser ablation method, PVD method, or plasma CVD method, laser CVD method, thermal CVD method, vapor phase synthesis method, vapor phase growth method, and catalytic chemical vapor deposition method. can do. The structure generally has a diameter of 0.1 nm to 300 nm, and the diameter of the pores 22 may also be varied according to the diameter of the structure to manufacture the first cathode plate 100.

For example, the size of the pores 22 implemented in AlPO ₄ is known to be about 0.73 nm, in which one carbon nanotube structure having a diameter of about 0.4 nm may be grown on the cathode electrode 10. In addition, in the porous alumina capable of implementing mesoporous or macroporous bodies, a plurality of the structures may be grown on the cathode electrode 10.

Although not described in detail, the surface of the cathode electrode 10 defined by the pores 22 may be pretreated under conditions where the electron-emitting body 20 may be filled or grown. Such a pretreatment procedure will typically be apparent to the person engaged in the present invention. In addition, the method of combining the microporous body 30 with the cathode electrode 10 and the method of restricting the electron emitter 20 to the pores 22 may be sufficiently realized through methods such as polishing, etching, and cleaning. have.

The adjusting layer 12 applied to the first cathode plate 100 may be used for various purposes. Specifically, the binding layer 12 improves the bonding force between the cathode electrode 10 and the electron-emitting body 10, or adjusts the height of the electron-emitting body 20 occupying the pores 22, or the control layer Combination of the 12 and the electron-emitting body 20 can implement a complex field emission effect.

The control layer 12 may be made of the same material or different materials as those of the cathode electrode 10, and may include tungsten (W), niobium (Nb), tantalum (Ta), molybdenum (Mo), chromium (Cr), and aluminum (Al). ), Metals such as copper (Cu), alloys or compounds containing these metal elements (for example, nitrides such as TiN, silicides such as WSi ₂ , MoSi ₂ , TiSi ₂ , TaSi ₂ ), and silicon (Si) Semiconductor or ITO (indium tin oxide) can be used.

When the adjusting layer 12 is made of the same material as the cathode electrode 10, the microporous body 30 is brought into contact with the molten cathode electrode 10 while the cathode electrode 10 is molten, and then subjected to capillary action. The adjustment layer 12 can be formed by this. At this time, the thickness of the adjustment layer 12 may be determined by varying the pressure to contact, the size of the pores, the time of contact, and the like. According to the method as described above, the bonding force between the microporous body 30 and the cathode electrode 10 can be improved, and the height of the adjustment layer 12 can be adjusted by the surface tension, so that the control layer 12 of various forms Can be implemented.

On the other hand, if there is an open space between each of the pores 22, the control layer 12 may be bonded to each other through the open space between each of the pores 22 may be a connection layer (14). The connection layer 14 may be an unavoidable choice depending on the shape of the microporous body 30, and the electron-emitting body 20 to be implemented in the present invention is exposed to the portion of the microporous body 30 to emit electrons. This is because it may be limited to a face (eg, a face opposite to the cathode electrode).

Although not described in detail, the upper surface of the control layer 12 defined by the pores 22 may be pretreated under conditions where the electron-emitting body 20 may be filled or grown. Such a pretreatment procedure will typically be apparent to the person engaged in the present invention. In addition, the method of allowing the electron-emitting body 20 to be limited to the pores 22 may be sufficiently implemented through methods such as polishing, etching, and cleaning.

In the first cathode plate 100 of the present invention, the current emitted from the electron-emitting body 20 is stabilized by limiting the electron-emitting body 20 in the pores 22, and the thermal and structural properties of the first cathode plate 100 are determined by the microporous body 30. And an electrically stable cathode plate. In particular, in the case of the carbon nanotube structure, by filling it in the pores 22 can solve the conventional problem that the carbon nanotubes are not agglomerated or straight aligned with each other. In addition, the control layer 12 may be electrically connected to open spaces between the pores 22 to correspond to the shapes of the various microporous bodies 30.

2 is a perspective view showing a second cathode plate 200 which is one example of the cathode plate of the present invention. Here, the first cathode plate is provided except that the plurality of microporous bodies 30 described in FIGS. 1 and 2 are supported by the support 40 so that each of the microporous bodies 30 is disposed separately from each other. Same as (100). Accordingly, the electron-emitting body 20 uses the same reference numerals as in FIG. 1, and a detailed description of parts other than the support 40 will be omitted.

Referring to FIG. 2, the support 40 applied to the second cathode plate 200 may be used for various purposes. Specifically, by arranging the plurality of microporous bodies 30 by the support body 40, the area of the second cathode plate 200 is increased or the microporous bodies 30 that are difficult to grow in large areas are divided into several sectors. By separating and growing and arranging, an appropriate field emission effect can be obtained. In addition, the rigidity of the support body 40 itself may bring structural stability in the vacuum atmosphere in which the second cathode plate 200 is applied, and in the atmosphere in which the second cathode plate 200 is applied to the support body 40 itself. It can also impart the function of adsorbing impurities generated.

The support 40 may be made of a semiconductor material such as silicon, a carbon-based material such as diamond and DLC, or an inorganic material such as a material such as a metal material. The support 40 may have a separate pore having a different pore from the above microporous body 30. It may be a sieve or a material without pores. Looking at each representative characteristics of the inorganic material, for example, the semiconductor material is easy to secure the space in which the micropore 30 can be formed, the carbon-based material or the metal material is the micropore 30 It is easy to transfer the heat generated in the, the pore material may be coated with a material for the getter, such as Zr-Al alloy to improve the getter properties.

In some cases, the above materials and pores may be applied in combination with each other. For example, the support 40 can be divided into portions with and without pores. Even the support body 40 may be a macroporous body described above, and may have a structure in which the microporous body 30 is formed in the pores of the macroporous body.

3A is a cross-sectional view schematically showing a field emission display to which the first cathode plate 100 of the present invention is applied, and FIG. 4B is a cross-sectional view schematically showing a field emission display to which the second cathode plate 200 of the present invention is applied.

3A and 3B, first and second cathode plates 100 and 200 are placed on the substrate 400 in the displays. The substrate 400 may use an inorganic material such as glass, or may be used flexibly using an organic material such as synthetic resin.

The cathode panel CP includes the first and second cathode plates 100 and 200 and a plurality of cathode panels CP are formed in the form of a two-dimensional matrix in an effective area that is an area where electrons are emitted. The cathode panel CP is provided with a vacuum exhaust through hole (not shown), and a tube tube (not shown) which becomes a plasma immediately after the vacuum exhaust is connected. When the frame 420 is formed of ceramic or glass, the height is, for example, 1.0 mm. In some cases, only the adhesive layer may be used instead of the frame 420.

Specifically, the anode panel AP includes a substrate 460, a phosphor layer 440, and an anode electrode 430. In this case, the phosphor layer 440 may be formed in a predetermined pattern (stripe shape or dot shape) on the substrate 460, and the anode electrode 430 covers the entire surface of the effective region in which electrons are emitted, for example. It may be composed of an aluminum thin film. The black matrix 450 is formed on the substrate 460 between the phosphor layer 440 and the phosphor layer 440. Meanwhile, the black matrix 450 may be omitted.

In the case of a display displaying a single color, the phosphor layer 440 does not necessarily need to be installed according to a predetermined pattern. Further, an anode electrode 430 composed of a transparent conductive film such as ITO may be provided between the substrate 460 and the phosphor layer 440 or an anode electrode 430 composed of a transparent conductive film provided on the substrate 460. ) May be provided between the substrate 460 and the phosphor layer 440 or the anode electrode 430 composed of a transparent conductive film provided on the substrate 460 and the phosphor layer formed on the anode electrode 430. 440 and the black matrix 450, the phosphor layer 440 and the aluminum formed on the black matrix 450, it is also possible to constitute a light reflection conductive film electrically connected to the anode electrode 430. .

One pixel is constituted by the phosphor layers 440 arranged on the effective region of the first and second cathode plates 100 and 200 on the cathode panel CP side and the anode panel AP facing the cathode plates. . In the effective area, the relevant pixels are arranged, for example, in hundreds of thousands to millions.

Spacers 410 are disposed at equal intervals between the cathode panel CP and the anode panel AP so as to include an effective area as an auxiliary means for maintaining a constant distance between the two panels. The shape of the spacer 410 is not limited to the columnar shape, but may be rectangular, for example, and may be a stripe rib. In addition, the spacer 410 does not necessarily need to be disposed at all four corners of the cathode plate, and may be disposed at a wider interval, and the arrangement may be irregular.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but many variations and modifications may be made without departing from the scope of the present invention. It is possible.

1 is a perspective view showing a first cathode plate which is one example of a cathode plate of the present invention.

2 is a perspective view showing a second cathode plate which is one example of the cathode plate of the present invention.

3A is a cross-sectional view schematically showing a field emission display to which the first cathode plate of the present invention is applied, and FIG. 3B is a cross-sectional view schematically showing a field emission display to which the second cathode plate of the present invention is applied.

* Description of the symbols for the main parts of the drawings *

100; First cathode plate 200; Second cathode plate

10; Cathode electrode 12; Control layer

14; Connection layer 20; Electron emitter

22; Pore 30; Microporous body

40; Support AP; Anode panel

CP; Cathode panel 400; Board

410; Spacer 420; Framework

430; Anode electrode 440; Phosphor layer

450; Black matrix

Claims

Microporous bodies including micropores and being insulators;

An electron emitter filled in the fine pores; And

And a cathode disposed on one side of the electron-emitting body and electrically connected to the electron-emitting body and including a cathode electrode on which the micro-pores are placed.

The field emission cathode plate according to claim 1, wherein the microporous body is any one selected from inorganic oxide pore bodies or two or more kinds of compound pore bodies.

The field emission cathode plate according to claim 1, wherein the electron-emitting body is a tip type or a flat type.

The field emission cathode plate according to claim 1, wherein the electron-emitting body is any one selected from a metal material, a semiconductor material, and a carbon-based material, or a combination thereof.

The field emission cathode plate of claim 4, wherein the carbon-based material is carbon nanotubes.

The field emission cathode plate as claimed in claim 5, wherein one or more carbon nanotubes are positioned in the pores.

The field emission cathode plate of claim 1, further comprising a control layer formed of the same material as the cathode electrode or a different material between the electron emission body and the cathode electrode.

8. The field emission cathode plate according to claim 7, wherein the control layer is bonded to each other through an open space between pores of the microporous body.

According to claim 1 or claim 7, wherein the microporous body is a plurality of microporous body characterized in that it further comprises a support for each of the microporous body is disposed separately from each other between the microporous body Field emission cathode plate.

The field emission cathode plate as claimed in claim 9, wherein the support is any one selected from the semiconductor material, the carbon material, and the metal material, or a combination thereof.

10. The field emission cathode plate of claim 9, wherein the support comprises a separate pore body having pores of a different size from the micropore body.

12. The field emission cathode plate of claim 11 wherein the externally exposed surface of the separate pore is covered with a material for the getter.

An anode panel and a cathode panel disposed to face each other at regular intervals;

A spacer for sealing the inside with a vacuum while maintaining a gap between the two panels;

In a field emission display having an anode electrode and a cathode plate respectively disposed on opposite surfaces of the two panels,

The cathode plate is

Microporous bodies including micropores and being insulators;

An electron emitter filled in the fine pores; And

A field emission display using a field emission cathode plate using a microporous body disposed on one side of the electron-emitting body and electrically connected to the electron-emitting body and including a cathode electrode on which the microporous body is placed.

The field emission display according to the field emission cathode plate using the microporous body according to claim 13, wherein the microporous body is any one selected from inorganic oxide pore bodies or two or more kinds of compound pore bodies.

The field emission display of claim 13, wherein the electron emission body is a tip type or a planar type.

The field emission display of claim 13, wherein the electron emission body is any one selected from a metal material, a semiconductor material, and a carbon-based material, or a combination thereof.

17. The field emission display of claim 16, wherein the carbon-based material is carbon nanotubes.

The field emission method of claim 13, further comprising a control layer formed of the same material as the cathode electrode or a different material between the electron emitter and the cathode electrode. display.

19. The microporous body according to claim 13 or 18, wherein the microporous body is provided in plural and further comprising a support for allowing the microporous bodies to be separated from each other. Field emission display by using field emission cathode plate.

20. The field emission display of claim 19, wherein the support comprises a separate pore body having pores of a different size from the micropore body.

21. The field emission display according to claim 20, wherein the surface of the pore exposed to the outside in the separate pore is covered with a material for getter.