KR20070083119A - Electron emission display device - Google Patents

Abstract

An electron emission display device is provided to remove a track of a spacer from a screen by suppressing the generation of abnormal emission of a phosphor layer around the spacer. A first substrate(10) and a second substrate(12) are disposed opposite to each other. A plurality of electron emission units(20) are formed on the first substrate. A plurality of driving electrodes are provided on the first substrate in order to control emission of electrons from the electron emission units. A plurality of phosphor layers are formed on one surface of the second substrate. A plurality of spacers(32) are positioned between the first and second substrates. A conductive layer(34) is positioned between at least one driving electrode and the spacers along a thickness direction of the first substrate. The conductive layer has larger area than the spacer toward the first substrate.

Description

Electron Emission Display Device {ELECTRON EMISSION DISPLAY DEVICE}

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 partial plan view of the electron emission device and the spacer shown in FIG. 1.

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 installed inside a vacuum container to support a compressive force applied to the vacuum container.

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 the first substrate to form an electron emission device, and the electron emission device is coupled to a second substrate having a light emitting unit including a fluorescent layer, a black layer, an anode electrode, and the like. To form an electron emission display device.

The electron emitting device has a driving electrode composed of scan electrodes and data electrodes in addition to the electron emitting part to emit an intended amount of electrons toward the second substrate in units of pixels, and the electron emitting display device emits at the electron emitting part The fluorescent layer is excited with the electrons to emit light or display light.

In the electron emission display device, the first substrate and the second substrate are integrally bonded to each other by the sealing member, and then the inner space is evacuated to a vacuum of approximately 10 ⁻⁶ Torr to form a 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 for supporting a compressive force applied to a vacuum container by providing a plurality of spacers between the first substrate and the second substrate and maintaining a constant gap between the two substrates has been developed and used. The spacer is mainly made of a dielectric such as glass, ceramic or tempered glass, and is positioned corresponding to the black layer so as not to invade the fluorescent layer.

However, the above-described spacer is charged with a positive or negative potential according to the material properties (dielectric constant, secondary electron emission coefficient, etc.) when an external factor such as electric field change inside the vacuum vessel in which the spacer is located.

In particular, when the spacer is positioned over the scan electrodes or the data electrodes with the insulating layer interposed therebetween, the surface potential of the spacer is influenced by the drive signal applied to the scan electrodes or the data electrodes, so that the drive signals are applied to the electrodes. The spacer surface is more easily charged when is applied.

The charged spacer distorts the electron beam path running around the spacer so that the electron beam spot reaching the second substrate is attracted or pushed away from the spacer. As a result, the fluorescent layer around the spacers emits light excessively or underlights, thereby causing display defects in which the spacers are visible on the screen.

Accordingly, the present invention is to solve the above problems, an object of the present invention is to suppress the surface charging of the spacer due to the driving voltage applied to the scan electrodes or data electrodes to minimize the electron beam path distortion around the spacer An electron emission display device is provided.

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

A first substrate and a second substrate disposed to face each other, electron emission portions formed on the first substrate, drive electrodes provided on the first substrate to control electron emission of the electron emission portions, and a surface of the second substrate. An electron emission display device including fluorescent layers formed, spacers positioned between the first substrate and the second substrate, and a conductive film positioned between the spacer and at least one driving electrode along the thickness direction of the first substrate To provide.

The conductive layer may be formed to have an area larger than one surface of the spacer facing the first substrate.

The electron emission display device may further include a focusing electrode positioned to be insulated from the driving electrodes on the driving electrodes.

The driving electrodes may include cathode electrodes and gate electrodes formed along a direction crossing each other with a first insulating layer interposed therebetween, and the focusing electrode may be positioned above the driving electrodes with a second insulating layer interposed therebetween. have.

When the gate electrodes are positioned on the cathode electrodes, the spacers may be disposed to correspond to the gate electrodes, and the conductive layer may be disposed to be parallel to the gate electrodes on the first insulating layer.

The conductive layer may be made of a metal material such as gate electrodes.

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

1 and 2 are partially exploded perspective and partial cross-sectional views of an electron emission display device according to an exemplary embodiment of the present invention, and FIG. 3 is a partial plan view of the electron emission device and the spacer shown in FIG. 1.

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.

If the cross region of the cathode electrodes 14 and the gate electrodes 18 is defined as a pixel region, electron emission portions 20 are formed in each pixel region over the cathode electrodes 14. In addition, openings 161 and 181 corresponding to the electron emission parts 20 are formed in the first insulating layer 16 and the gate electrodes 18 to expose the electron emission parts 20 on the first substrate 10. do.

The electron emission unit 20 may be formed of materials emitting electrons, for example, carbon-based materials or nanometer-sized materials when an electric field is applied in a vacuum. The electron emission unit 20 may include, for example, carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, fullerenes (C ₆₀ ), silicon nanowires, or a combination thereof, and the screen may be manufactured by the method. Printing, direct growth, sputtering or chemical vapor deposition can be applied.

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, and passes the electron beam through the focusing electrode 22 and the second insulating layer 24. Openings 221 and 241 are formed.

The focusing electrode 22 forms an opening corresponding to each electron emission part 20 to focus electrons emitted from each electron emission part 20 individually, or to form one opening 221 for each pixel area. The electrons emitted from the pixel region of the lens may be collectively focused. The second case is shown in the figure.

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 are spaced apart from each other. The black layer 28 is formed between the fluorescent layers 26 to improve contrast of the screen. The fluorescent layer 26 is disposed so that the fluorescent layer of one color corresponds to the pixel area set in the first substrate 10.

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 receives the high voltage necessary for accelerating the electron beam from the outside to maintain the fluorescent layer 26 in a high potential state, and visible light emitted toward the first substrate 10 of the visible light emitted from the fluorescent layer 26. Is reflected toward the second substrate 12 to increase the brightness of the screen.

The anode electrode may be formed of a transparent conductive film such as indium tin oxide (ITO). In this case, the anode electrode is positioned on one surface of the fluorescent layer 26 and the black layer 28 facing the second substrate 12. Moreover, the structure which forms simultaneously the above-mentioned metal film and a transparent conductive film as an anode electrode is also possible.

In addition, 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 spacer 32 is made of glass, ceramic, tempered glass, or the like, and is positioned corresponding to the black layer 28 between the pixel regions so as not to invade the fluorescent layer 26. The spacer 32 may be formed in various shapes such as a rod or column, and in the drawing, only one rod-shaped spacer is illustrated for convenience.

The spacer 32 is positioned correspondingly between the gate electrodes 18 or between the cathode electrodes 14 on the focusing electrode 22. When the spacer 32 has a rod shape, the spacer 32 is disposed so that its longitudinal direction is parallel to the longitudinal direction of the gate electrode 18 (x-axis direction in the drawing) at a position between the gate electrodes 18, or In the position between the cathode electrodes 14, its longitudinal direction is arranged parallel to the longitudinal direction (y-axis direction in the drawing) of the cathode electrode 14. The first case is shown in the figure.

In the above-described spacer 32 mounting structure, the spacer 32 is disposed on the cathode electrodes 14 with the first insulating layer 16 and the second insulating layer 24 interposed therebetween, so that the spacer 32 is disposed on the first substrate 10. The cathode electrodes 14 and the spacers 32 overlap each other along the thickness direction (the z-axis direction in the drawing).

In the present exemplary embodiment, a driving voltage applied to the cathode electrodes 14 between the cathode electrodes 14 and the spacer 32 along the thickness direction of the first substrate 10 affects the surface potential of the spacer 32. A conductive film 34 is formed to block it from reaching. The conductive film 32 is a kind of floating electrode which does not receive a voltage from the outside, and is disposed under the spacer 32 at each mounting position of the spacer 32.

More specifically, the conductive layer 34 may be disposed between the gate electrodes 18 on the first insulating layer 16, and may have a larger width than the spacer 32 and a greater length than the spacer 32. have. That is, the conductive film 34 is formed to have a larger area than the bottom surface of the spacer 32 in contact with the focusing electrode 22 to effectively block the influence of the driving voltage applied to the cathode electrodes 14.

The conductive layer 34 may be made of the same metal material as the gate electrode 18. In this case, since the gate electrodes 18 and the conductive film 34 can be completed simultaneously in one patterning process, there is an effect of simplifying the manufacturing process of the electron emission device.

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. The focusing electrode 22 receives a voltage required for electron beam focusing, for example, 0 V or a negative DC voltage, and the anode electrode 30 applies a voltage required for electron beam acceleration, for example, a positive DC voltage of several hundreds to thousands of volts. Receive.

Then, in the pixels where the voltage difference between the cathode electrode 14 and the gate electrode 18 is greater than or equal to the threshold, an electric field is formed around the electron emission part 20 to emit electrons therefrom. The emitted electrons are focused through the opening 221 of the focusing electrode 22 to the center of the electron beam bundle, and are attracted by the high voltage applied to the anode electrode 30 to collide with the fluorescent layer 26 of the corresponding pixel to emit light. Let's do it.

In the aforementioned driving process, a driving voltage in which the conductive film 34 positioned between the cathode electrodes 14 and the spacer 32 is applied to the cathode electrodes 14, for example, a data driving voltage is applied to the surface of the spacer 32. By blocking the influence on the potential, the surface charging of the spacer 32 is suppressed. Accordingly, the spacer 32 may suppress abnormal light emission when the fluorescent layer 26 around the spacer 32 emits light excessively or under light by minimizing electron beam path distortion traveling around the spacer 32.

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, the electron emission display device of the present invention suppresses the surface potential change of the spacer due to the driving voltage applied to the driving electrodes to minimize the surface charging of the spacer. Accordingly, in the electron emission display device according to the present invention, no abnormal emission occurs when the fluorescent layer around the spacer emits excessive light or under emits light, and the spacer is not visible on the screen, thereby achieving excellent display quality.

Claims (8)

A first substrate and a second substrate disposed to face each other; Electron emission parts formed 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; Spacers positioned between the first substrate and the second substrate; And A conductive film positioned between the at least one driving electrode and the spacer along a thickness direction of the first substrate Electron emission display device comprising a. The method of claim 1, And the conductive film has an area larger than one surface of the spacer facing the first substrate. The method according to claim 1 or 2, And a focusing electrode positioned to be insulated from the driving electrodes on the driving electrodes. The method of claim 3, The driving electrodes include cathode electrodes and gate electrodes formed along a direction crossing each other with a first insulating layer interposed therebetween, And the focusing electrode is positioned above the driving electrodes with a second insulating layer interposed therebetween. The method of claim 4, wherein And the gate electrodes are positioned above the cathode electrodes and the spacers are correspondingly positioned between the gate electrodes. The method of claim 5, And the conductive layer is disposed in parallel with the gate electrodes on the first insulating layer. The method of claim 6, The electron emission display device of which the conductive film is made of the same material as the gate electrodes. The method of claim 1, And an anode electrode positioned on one surface of the fluorescent layers and the black layer, wherein the spacer is positioned corresponding to the black layer.

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