KR20070044580A - Spacers and electron emission display device with the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron emission display device capable of suppressing electron beam distortion and display quality deterioration due to spacer charging, wherein the electron emission display device according to the present invention comprises: a first substrate and a second substrate facing each other; Electron emission portions provided on the substrate, drive electrodes provided on the first substrate to control electron emission of the electron emission portions, fluorescent layers formed on one surface of the second substrate, and an anode positioned on one surface of the fluorescent layers An electrode and spacers positioned between the first substrate and the second substrate. Each spacer consists of a matrix having a dielectric constant of less than 100 and a coating layer provided on at least one surface of the matrix and having a secondary electron emission coefficient of 3 or less.

Electron emission unit, fluorescent layer, driving electrode, anode electrode, spacer, matrix, coating layer, dielectric constant, secondary electron emission coefficient

Description

Spacer and Electron Emission Display Device Having the Same {SPACERS AND ELECTRON EMISSION DISPLAY DEVICE WITH THE SAME}

1 is a partially exploded perspective view of an electron emission display device according to an exemplary embodiment of the present invention.

2 is a partial cross-sectional view of an electron emission display device according to an embodiment of the present invention.

3 is a photograph showing an emission pattern of a light emitting unit in an electron emission display device having a spacer according to an embodiment of the present invention.

4 is a photograph showing a light emission pattern of a light emitting unit in an electron emission display device of a comparative example.

5 is a partial cross-sectional view of an electron emission display device according to another exemplary embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron emission display device, and more particularly, to an electron emission display device having spacers disposed between a first substrate and a second substrate to maintain a constant gap between two substrates.

In general, electron emission elements may be classified into a method using a hot cathode and a cold cathode according to the type of electron source.

Here, the electron-emitting device using the cold cathode is a field emitter array (FEA) type, a surface conduction emission type (SCE) type, a metal-insulation layer-metal Metal (MIM) type and Metal-Insulator-Semiconductor (MIS) type are known.

The electron emission devices are arranged in an array on one substrate to form an electron emission device, and the electron emission device is combined with another substrate having a light emitting unit including a fluorescent layer and an anode electrode to display an electron emission display. A device (electron emission display device) is configured.

That is, the conventional electron emitting device includes a plurality of driving electrodes that function as scan electrodes and driving electrodes in addition to the electron emitting part, thereby turning on / off the electron emission and the amount of electron emission per pixel by the action of the electron emitting part and the driving electrodes. To control. In addition, the electron emission display device excites the fluorescent layer with electrons emitted from the electron emission unit to perform a predetermined light emission or display function.

In the above-mentioned electron emission display device, the first substrate provided with the electron emission parts and the driving electrodes and the second substrate provided with the light emitting unit are edge-bonded to each other by a sealing member and then the inner space has a vacuum degree of approximately 10 ^-6 torr. And the vacuum container together with the sealing member. The vacuum container receives a strong compressive force due to the pressure difference between the inside and the outside, and the compressive force increases in proportion to the screen size.

Therefore, a technique has been developed in which a plurality of spacers are provided between the first substrate and the second substrate to support the compressive force applied to the vacuum container, and to keep the distance between the two substrates constant. In this case, the spacer is mainly made of a dielectric such as glass or ceramic in order to prevent a short between the driving electrodes and the anode electrode, and is positioned corresponding to the black layer so as not to invade the fluorescent layer.

However, even when the electron emission display device includes a focusing electrode, it is difficult to ensure perfect electron beam straightness, so when electrons emitted from the electron emission portion of the first substrate are directed toward the second substrate on which the fluorescent layer is located. It spreads with a predetermined divergence angle. The electron beam spreading causes electrons to collide on the surface of the spacer, and the spacer on which the electrons collide is charged with a positive or negative potential according to the material properties (dielectric constant, secondary electron emission coefficient, etc.).

Charged spacers distort the electron beam path by changing the electric field around the spacers. For example, a spacer charged at a positive potential attracts an electron beam, and a spacer charged at a negative potential pushes the electron beam. Such electron beam path distortion hinders accurate color representation around the spacers and causes display quality degradation in which the spacers are perceived on the screen.

Accordingly, an object of the present invention is to solve the above-described problem, and an object of the present invention is to provide a spacer capable of suppressing electron beam distortion and display quality deterioration due to spacer charging so that a spacer surface is not charged, and an electron emission display device having the same. To provide.

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

A spacer installed inside a vacuum vessel to support a compressive force applied to the vacuum vessel, the spacer including a matrix and a coating layer provided on at least one surface of the matrix, wherein the matrix has a dielectric constant of less than 100, and the coating layer is 2 or less. A spacer having a difference electron emission coefficient is provided.

The matrix may be made of any one of glass, ceramic, glass-ceramic mixture, tempered glass, and ceramic-tempered glass mixture.

The coating layer may be made of any one material selected from the group consisting of copper oxide, carbon, titanium oxide, vanadium oxide, chromium oxide, and polyimide, and may be formed on the side of the mother body.

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

A first substrate and a second substrate disposed to face each other, electron emission portions provided on the first substrate, driving electrodes provided on the first substrate to control electron emission of the electron emission portions, and a surface of the second substrate. A fluorescent material to be formed, an anode electrode located on one surface of the fluorescent layers, spacers located between the first and second substrates, each spacer having a dielectric constant of less than 100, An electron emission display device comprising a coating layer provided on at least one surface and having a secondary electron emission coefficient of 3 or less.

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

1 and 2 are partial exploded perspective and partial cross-sectional views of an electron emission display device according to an embodiment of the present invention, respectively, showing a field emission array (FEA) type electron emission display device.

Referring to the drawings, the electron emission display device includes a first substrate 10 and a second substrate 12 which are disposed in parallel to each other at predetermined intervals. Sealing members (not shown) are disposed at the edges of the first substrate 10 and the second substrate 12 to bond the two substrates, and the internal space is evacuated with a vacuum of approximately 10 ⁻⁶ torr to form the first substrate 10. ), The second substrate 12 and the sealing member constitute a vacuum container.

On the opposite surface of the first substrate 10 to the second substrate 12, electron emission elements are arranged in an array to form the electron emission device 100 together with the first substrate 10, and the electron emission device ( 100 is combined with the second substrate 12 and the light emitting unit 110 provided on the second substrate 12 to form an electron emission display device.

First, the cathode electrodes 14, which are first electrodes, are formed in a stripe pattern along one direction of the first substrate 10 on the first substrate 10, and cover the cathode electrodes 14. 10) The first insulating layer 16 is formed on the whole. Gate electrodes 18, which are second electrodes, are formed on the first insulating layer 16 in a stripe pattern along a direction orthogonal to the cathode electrodes 14.

In the present exemplary embodiment, when the intersection area between the cathode electrode 14 and the gate electrode 18 is defined as a pixel area, the electron emission parts 20 are formed in each pixel area over the cathode electrode 14, and the first insulating layer ( Openings 161 and 181 corresponding to the electron emission portions 20 are formed in the 16 and the gate electrode 18 to expose the electron emission portions 20 on the first substrate 10.

The electron emission unit 20 may be formed of materials that emit electrons when an electric field is applied in a vacuum, such as a carbon-based material or a nanometer (nm) size material. The electron emission unit 20 may include, for example, carbon nanotubes (CNT), graphite, graphite nanofibers, diamonds, diamond-like carbons (DLC), fullerenes (C ₆₀ ), silicon nanowires, and combinations thereof. have. On the other hand, the electron emission unit may be formed of a tip structure having a pointed tip mainly made of molybdenum (Mo) or silicon (Si).

In the drawing, the circular electron emitters 20 are arranged in a line along the longitudinal direction of the cathode electrode 14, but the shape of the electron emitter 20, the number and arrangement per pixel area, etc. are illustrated. It is not limited to the example and can be variously modified.

In addition, the structure in which the gate electrodes 18 are positioned above the cathode electrodes 14 with the first insulating layer 16 interposed therebetween, but the gate electrodes 18 are disposed with the first insulating layer interposed therebetween. A structure located below the electrodes is also possible. In this case, the electron emission part may be formed on the side of the cathode electrode on the first insulating layer.

The focusing electrode 22, which is a third electrode, is formed on the gate electrodes 18 and the first insulating layer 16. A second insulating layer 24 is positioned below the focusing electrode 22 to insulate the gate electrodes 18 and the focusing electrode 22. The focusing electrodes 22 and the second insulating layer 24 are also provided with openings 221 and 241 for passing electron beams. The openings 221 and 241 are provided for example in each pixel area so that the focusing electrode 22 is provided. It comprehensively focuses electrons emitted from one pixel area.

Next, on one surface of the second substrate 12 opposite to the first substrate 10, the fluorescent layer 26, for example, the red, green, and blue fluorescent layers 26R, 26G, and 26B may be disposed on each other. It is formed at intervals, and a black layer 28 is formed between the fluorescent layers 26 to improve contrast of the screen. An anode electrode 30 made of a metal film such as aluminum (Al) is formed on the fluorescent layer 26 and the black layer 28.

The anode electrode 30 is applied with a high voltage necessary for accelerating the electron beam from the outside to maintain the fluorescent layer 26 in a high potential state, and radiated toward the first substrate 10 of the visible light emitted from the fluorescent layer 26. The visible light is reflected toward the second substrate 12 to increase the brightness of the screen.

On the other hand, the anode electrode may be made of a transparent conductive film such as ITO, in which case the anode electrode is located on one surface of the fluorescent layer 26 and the black layer 28 facing the second substrate 12. Moreover, the structure which uses simultaneously the above-mentioned transparent conductive film and a metal film as an anode electrode is also possible.

Spacers 32 are disposed between the first substrate 10 and the second substrate 12 to support the compressive force applied to the vacuum container and to keep the distance between the two substrates constant. The spacers 32 are positioned corresponding to the black layer 28 so as not to invade the fluorescent layer 26, and the wall-type spacer is illustrated in the drawing as an example.

In the present embodiment, the spacer 32 includes a matrix 321 having a dielectric constant of less than 100 and a coating layer 322 having a secondary electron emission coefficient of 3 or less.

The matrix 321 reduces the reverse potential caused by the spacer charging, thereby minimizing the electron beam distortion, and suppresses the arc discharge to prevent the display device from being defective. That is, the higher the dielectric constant of the mother 321 is effective to reduce the reverse potential, but if the dielectric constant of 100 or more can cause arc discharge, the dielectric constant of the mother 321 is preferably less than 100. In addition, the coating layer 322 having a secondary electron emission coefficient of 3 or less is provided on the mother 321 side to serve to prevent the surface of the spacer 32 from being easily charged.

The matrix 321 may be made of glass, ceramic, glass-ceramic mixture, tempered glass, ceramic-tempered glass mixture, and the like that satisfy the above conditions. The coating layer 322 is formed on the entire side of the base 321 except for the top and bottom surfaces, and may be formed of copper oxide, carbon, titanium oxide, vanadium oxide, chromium oxide, or polyimide.

The spacer 32 including the matrix 321 and the coating layer 322 is not easily charged on the surface of the spacer 32 even when the electron beam collides, and minimizes the electron beam distortion due to the reverse potential.

The spacer 32 may be formed in various shapes such as a circular columnar shape and a cross column type in addition to the illustrated wall shape.

The electron emission display device having the above-described configuration is driven by supplying a predetermined voltage to the cathode electrodes 14, the gate electrodes 18, the focusing electrodes 22, and the anode electrodes 30 from the outside.

For example, any one of the cathode electrodes 14 and the gate electrodes 18 receives a scan driving voltage to serve as scan electrodes, and the other electrodes receive a data driving voltage to serve as data electrodes. In addition, the focusing electrode 22 receives a voltage required for electron beam focusing, for example, 0 V or a negative DC voltage of several to several tens of volts, and the anode electrode 30 requires a voltage for accelerating the electron beam, for example, several hundred to several thousand volts. DC voltage of is applied.

As a result, an electric field is formed around the electron emission part 20 in the pixels in which the voltage difference between the cathode electrode 14 and the gate electrode 18 is greater than or equal to the threshold, and electrons are emitted therefrom. The emitted electrons are focused to the center of the electron beam bundle while passing through the opening 221 of the focusing electrode 22, and attracted by the high voltage applied to the anode electrode 30 to impinge on the corresponding fluorescent layer 26 to emit light.

Despite the action of the focusing electrode 22 during the aforementioned driving process, electrons are emitted to the periphery of the electron beam bundle, and some of these electrons collide with the spacer 32. In this case, the surface of the spacer 32 of the present embodiment is not easily charged even when the electron beam collides due to the material properties of the matrix 321 and the coating layer 322, and does not cause electron beam distortion around the spacer 32.

3 is a photograph showing a light emission pattern of a light emitting unit in an electron emission display device of an embodiment equipped with a spacer having a dielectric constant of 80 and a chromium oxide coating layer, and FIG. 4 is a comparison with a spacer having no coating layer. It is a photograph which shows the light emission pattern of the light emitting unit in the electron emission display device of an example.

First, referring to FIG. 4, it can be seen that the electron beam distortion occurs in the center portion of the photograph in which the spacer is installed, so that the portion in which the spacer is installed is dark. On the other hand, although the spacer is installed at the same position in FIG. 3, it can be seen that the spacer is not recognized on the screen because electron beam distortion does not occur.

5 is a partial cross-sectional view of a surface conduction emission (SCE) type electron emission display device which is another embodiment of the electron emission display device according to the present invention. Since the configuration of the light emitting unit 110 provided on the spacer 32 and the second substrate 12 is made the same as the above-described field emission array (FEA) type electron emission display device, the configuration of the electron emission device 101 Only briefly explain.

Referring to the drawings, the first electrodes 36 and the second electrodes 38 are spaced apart from each other on the first substrate 34, and the respective electrodes are disposed on the first electrodes 36 and the second electrodes 38. The first conductive thin film 40 and the second conductive thin film 42 which are located close to each other while covering a portion of the surface of the metal are formed. An electron emission portion 44 is formed between the first conductive thin film 40 and the second conductive thin film 42 to be connected to the conductive thin films, and the electron emission portion 44 is formed of the conductive thin films 40 and 42. The first electrode 36 and the second electrode 38 are electrically connected to each other through the first electrode 36 and the second electrode 38.

The first electrode 36 and the second electrode 38 may be formed of various conductive materials, and the first conductive thin film 40 and the second conductive thin film 42 may include nickel (Ni), gold (Au), It consists of a thin film of fine particles using a conductive material such as platinum (Pt) and palladium (Pd). The electron emission section 44 is preferably formed of graphite carbon, a carbon compound, or the like, and carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, C, as in the field emission array (FEA) type described above. ₆₀ , silicon nanowires, and combinations thereof.

In the above-described structure, when a voltage is applied to the first electrode 36 and the second electrode 38, respectively, the surface of the electron emission part 44 through the first conductive thin film 40 and the second conductive thin film 42. When the current flows in a horizontal direction, the surface conduction electrons are emitted, and the emitted electrons are attracted to the second substrate 12 by the high voltage applied to the anode electrode 30 and collide with the corresponding fluorescent layer 26. To emit light.

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

As described above, since the electron emission display device according to the present invention includes a spacer composed of the above-described matrix and the coating layer, even if electrons emitted from the electron emission portion collide with the spacer surface, the surface of the spacer is not charged and thus the electric field changes around the spacer. Does not occur. Therefore, accurate color can be realized around the spacer, and the display quality can be improved by preventing the recognition of the spacer on the screen.

Claims (8)

A spacer installed in a vacuum container to support a compressive force applied to the vacuum container, the spacer comprising a mother and a coating layer provided on at least one surface of the mother, The parent has a dielectric constant of less than 100, And a spacer having a secondary electron emission coefficient of 3 or less. The method of claim 1, And a matrix comprising any one of glass, ceramic, glass-ceramic mixture, tempered glass, and ceramic-tempered glass mixture. The method of claim 1, The spacer layer is made of any one material selected from the group consisting of copper oxide, carbon, titanium oxide, vanadium oxide, chromium oxide and polyimide. The method of claim 1, The spacer layer is provided on the side of the matrix. A first substrate and a second substrate disposed to face each other; Electron emission parts provided on the first substrate; Drive electrodes provided on the first substrate to control electron emission of the electron emission parts; Fluorescent layers formed on one surface of the second substrate; An anode located on one surface of the fluorescent layers; And Spacers positioned between the first substrate and the second substrate, Each of the spacers, A mother having a dielectric constant of less than 100; And a coating layer provided on at least one surface of the matrix and having a secondary electron emission coefficient of 3 or less. The method of claim 5, An electron emission display device in which the matrix is made of any one of glass, ceramic, glass-ceramic mixture, tempered glass, and ceramic-tempered glass mixture. The method of claim 5, An electron emission display device in which the coating layer is made of any one material selected from the group consisting of copper oxide, carbon, titanium oxide, vanadium oxide, chromium oxide, and polyimide. The method of claim 5, And the coating layer is provided on the side of the matrix.

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