KR20080042277A - Spacers and Electron Emission Display Devices Having These Spacers - Google Patents

Abstract

In the spacer for an electron emission display device provided between the first substrate and the second substrate constituting the vacuum container to support the compressive force applied to the vacuum container so as to suppress electron beam distortion around the spacer and consequently deterioration of display quality. And an electron emission display device having an arbitrary height along the thickness direction of the first substrate and the second substrate, made of a high resistance body, divided into two or more layers in the height direction, and neighboring layers made of materials having different resistivities from each other. It provides a spacer for.

Description

Spacer and Electron Emission Display Device with The Same

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

2 is a partially exploded perspective view of a field emission array (FEA) type electron emission display device according to an embodiment of the present invention.

3 is a partial cross-sectional view of a field emission array (FEA) type electron emission display device in accordance with one embodiment of the present invention.

4 is a partial cross-sectional view of a surface conduction emission (SCE) type electron emission display device according to an embodiment of the present invention.

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

6 is an enlarged partial cross-sectional view showing a part of a spacer in another 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 spacers installed in a vacuum container to support a compressive force applied to the vacuum container, and an electron emission display device having the spacers.

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 field emission array (FEA) type electron emission device uses a principle that electrons are easily emitted by an electric field in vacuum when a material having a low work function or a high aspect ratio is used as an electron source. Molybdenum (Mo) Alternatively, an example has been developed in which an electron emission unit is formed of a tip structure having a sharp tip, mainly made of silicon (Si), or an electron emission unit is formed of a carbon-based material such as carbon nanotubes.

The surface conduction emission (SCE) type electron emission device forms an electron emission portion by providing a conductive thin film between a first electrode and a second electrode disposed to face each other on a substrate and providing a micro crack in the conductive thin film. By applying a voltage to both electrodes, a principle is used in which electrons are emitted from the electron emission unit when a current flows to the surface of the conductive thin film.

Metal-insulating layer-metal (MIM) type and metal-insulating layer-semiconductor (MIS) type electron emission devices have electron emission structures of metal / insulation layer / metal (MIM) and metal / insulation layer / semiconductor (MIS) structures, respectively. When a voltage is applied between two metals or metals and semiconductors having an insulating layer interposed therebetween, electrons supplied from the metal or semiconductor pass through the insulating layer and reach the upper metal by a tunneling phenomenon. In addition, a principle in which electrons having energy above a work function of the upper metal are emitted from the upper metal among the reached electrons is used.

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 combined with a second substrate having a light emitting unit composed of a fluorescent layer and an anode electrode to emit electrons. A display device (electron emission display device) is configured.

The electron emission device includes a plurality of driving electrodes that function as scan electrodes and data electrodes together with the electron emission portion to control the electron emission amount of the electron emission portions per unit pixel. The electron emission display device applies a high voltage to the anode electrode to accelerate electrons emitted from the first substrate side toward the second substrate, and these electrons excite the fluorescent layer to emit visible light, thereby making a predetermined light emission or display.

In the electron emission display device, the first substrate and the second substrate are edge-bonded to each other by a sealing member such as a frit bar, and then the internal space is evacuated to a vacuum of approximately 10 ^-6 Torr so that the vacuum container together with the sealing member is removed. Configure 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, the vacuum container supports a compression force applied to the vacuum container by installing a plurality of spacers therein, and maintains a constant gap between the first substrate and the second substrate. In this case, the spacer is mainly made of a high resistance body such as glass or ceramic so that the driving electrodes on the first substrate and the anode electrode on the second substrate are not short-circuited through the spacer.

However, in the conventional electron emission display device, electrons emitted from the electron emission portion tend to spread with a predetermined divergence angle instead of going straight toward the second substrate. Due to the electron beam spread, electrons collide with the surface of the spacer, and the spacer where the electron collides is charged with a positive or negative potential according to the material properties (dielectric constant or secondary electron emission coefficient), and the charged spacer Distorts the electron beam path by changing the surrounding electric field. For example, a spacer charged at a positive potential attracts an surrounding electron beam, and a spacer charged at a negative potential pushes the surrounding electron beam. Such path distortion of the electron beam interferes with accurate color representation around the spacer, and causes display quality deterioration in which the spacer spot is visible on the screen.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to stack two or more layers of materials having different resistivity in the vertical direction to suppress electron beam distortion around the spacer and consequently deterioration of display quality. And an electron emission display device having the spacer.

In order to achieve the above object, the present invention relates to a spacer for an electron emission display device which is provided between a first substrate and a second substrate constituting a vacuum container to support a compressive force applied to the vacuum container. Provided is a spacer for an electron emission display device having an arbitrary height along the thickness direction of two substrates, made of a high resistance material, divided into two or more layers in the height direction, and neighboring layers made of materials having different resistivity from each other.

In order to achieve the above object, the present invention provides a first substrate and a second substrate disposed opposite to each other, an electron emission device provided on the first substrate and composed of a plurality of electron emission elements, and a second substrate. And a light emitting unit including fluorescent layers and an anode electrode positioned on one surface of the fluorescent layers, and a plurality of spacers positioned between the first substrate and the second substrate, wherein the spacers include a first substrate and a second substrate. The present invention provides an electron emission display device having a predetermined height along a thickness direction of a layer, and made of a high resistance material, divided into two or more layers in a height direction, and neighboring layers made of materials having different resistivities from each other.

The electron emission device may be any one of a field emission array (FEA) type, a surface conduction emission (SCE) type, a metal-insulating layer-metal (MIM) type, and a metal-insulating layer-semiconductor (MIS) type.

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

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

Referring to the drawings, the electron emission display device includes a first substrate 10 and a second substrate 12 which are arranged 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) and 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 100 are arranged in an array to form the electron emission device 101 together with the first substrate 10, The emission device 101 is combined with the light emitting unit 102 provided on the second substrate 12 and the second substrate 12 to form an electron emission display device.

The electron emission device 100 includes an electron emission unit and driving electrodes to form a basic unit for controlling ON / OFF of electron emission and an electron emission amount, and are disposed for each unit pixel on the first substrate 10.

The light emitting unit 102 includes a fluorescent layer 14, for example, red, green, and blue fluorescent layers 14R, 14G, 14B, and a black layer 16 positioned between the fluorescent layers 14. ) And an anode electrode 18 positioned on either surface of the fluorescent layers 14 and the black layer 16. The fluorescent layer 14 is disposed so that one fluorescent layer 14R, 14G, 14B corresponds to each electron emission element 100. In the drawing, for example, the anode electrode 18 is positioned on one surface of the fluorescent layers 14 facing the first substrate 10 and the black layer 16.

Spacers 20 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 gap between the first substrate 10 and the second substrate 12 constant. do. The spacers 20 are positioned to correspond to the black layer 16 so as not to invade the fluorescent layer 14 and have a predetermined height along the thickness direction of the two substrates 10 and 12.

In the above-described configuration, the electron emission device emits electrons by the action of the electron emission unit and the driving electrodes for each electron emission element 100, and the anode electrode 18 is applied with a high voltage (approximately several to several tens of kV). A predetermined display action is performed by accelerating electrons toward the second substrate 12, and accelerating electrons collide with the fluorescent layer 14 of the corresponding unit pixel to emit light.

In this process, the light emitting unit 102 has a voltage difference of several to several tens of kV corresponding to the magnitude of the anode voltage with respect to the electron emitting device 101. This generates a voltage gradient in which the voltage gradually rises from the electron emitting device 101 toward the light emitting unit 102 in the vacuum region between the first substrate 10 and the second substrate 12.

In addition, the electrons emitted from each of the electron emission devices 100 in the driving process described above spread toward the second substrate 12, and as a result, some of the electrons collide with the surface of the spacer 20.

In the spacer 20 of the present embodiment, the equipotential lines are deformed under the driving environment of the electron emission display device through the following configuration to minimize the electron beam distortion due to the charging of the spacer 20.

In the present embodiment, the spacer 20 is made of a high resistance material, the lower layer 22 positioned on the side facing the first substrate 10 (the side closer to the first substrate 10), and the second substrate. It consists of the upper layer 24 located in the side toward (12) (the side near the said 2nd board | substrate 12). In this case, the lower layer 22 and the upper layer 24 are formed of materials having different specific resistances.

The lower layer 22 and the upper layer 24 overlap each other to form one spacer 20.

The lower layer 22 and the upper layer 24 are made of a high-resistance member instead of a complete insulator in order to remove the charge caused by the collision of electrons. For example, the lower layer 22 and the upper layer 24 may be made of a high resistance material such as glass, tempered glass, ceramic or glass-ceramic mixture, silicon oxide, or the like, and may be formed in various shapes such as a columnar shape or a rod shape.

When a current flows through the spacer 20 made of a high resistor in this manner under high voltage, the current density J at this time is determined by the potential difference between both ends of the spacer 20 and the total resistance in the height direction of the spacer 20. .

Moreover, this current density J must be kept constant within the spacer 20. If the spacer 20 has a partly different resistivity p, the strength E of the electric field formed in that part is different. Will also change. That is, the intensity E of the electric field formed at a specific portion of the spacer 20 is determined by the specific resistance ρ and the current density J of the portion (E = ρJ).

Therefore, when the spacers 20 are formed by stacking the lower layer 22 and the upper layer 24 formed using materials having different specific resistances, deformation of the equipotential lines occurs as compared with forming the entirety of the materials having the same specific resistance. . In the present invention, by using the deformation of the equipotential line, the trajectory of the electron beam that is distorted by the charging of the spacer 20 due to the collision of electrons is controlled.

2 shows another embodiment of the spacer 20 according to the present invention.

In the present embodiment, the spacer 20 further includes an intermediate layer 26 between the lower layer 22 and the upper layer 24.

The intermediate layer 26 is formed of a material having a specific resistance different from that of the lower layer 22 and the upper layer 24.

Since the lower layer 22 and the upper layer 24 are positioned apart from each other with the intermediate layer 26 therebetween, the lower layer 22 and the upper layer 24 may be formed of a material having the same specific resistance.

The lower layer 22, the upper layer 24, and the intermediate layer 26 may be formed of materials having different specific resistances, respectively.

In the above-described embodiment, the spacer 20 is described as being formed of two or three layers. However, the spacer 20 may be formed of four or more layers, and each layer may be formed of a material having a different specific resistance. The materials having the same specific resistance may be alternately positioned to be formed, the specific resistance may be sequentially formed, and the specific resistance may be sequentially reduced.

As described above, in the spacer 20 according to the exemplary embodiment of the present invention, since the neighboring layers have different specific resistances, the equipotential lines may be modified, and the electron beam trajectory traveling around the spacer 20 may be adjusted. Therefore, the electron emission display device of the present embodiment can correct the color of the electron beam by adjusting the trajectory of the electron beam even when the spacer 20 is charged, and solve the problem of the spacer 20 being visible on the screen. have.

The above-mentioned electron emission display device can be any one of a field emission array (FEA) type, a surface conduction emission (SCE) type, a metal-insulating layer-metal (MIM) type, and a metal-insulating layer-semiconductor (MIS) type. It may be made of a device.

3 and 4, the structure of the field emission array (FEA) type electron emission display device will be described, and the structure of the surface conduction emission type (SCE) type electron emission display device will be described with reference to FIG. 5. do.

3 and 4 are partial exploded perspective and partial cross-sectional views, respectively, of a field emission array type electron emission display device according to an embodiment of the present invention.

Referring to the drawings, the cathode electrodes 28, which are the 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 28. The first insulating layer 30 is formed on the entirety of (10). Gate electrodes 32, which are second electrodes, are formed on the first insulating layer 30 in a stripe pattern along a direction orthogonal to the cathode electrodes 28.

An intersection area between the cathode electrodes 28 and the gate electrodes 32 constitutes one unit pixel, and electron emission parts 34 are formed in each unit pixel on the cathode electrode 28. In addition, openings 301 and 321 corresponding to the electron emission parts 34 are formed in the first insulating layer 30 and the gate electrodes 32 to form the electron emission parts 34 on the first substrate 10. To be exposed.

The electron emission part 34 may be formed of materials emitting electrons, for example, a carbon-based material or a nanometer (nm) size material, when an electric field is applied in a vacuum. The electron emission part 34 may include, for example, carbon nanotubes (CNT), graphite, graphite nanofibers, diamonds, diamond-like carbons (DLC), fullerenes (C ₆₀ ), silicon nanowires, and combinations thereof. Direct growth, screen printing, chemical vapor deposition, or sputtering may be applied to the preparation method.

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 figure, the circular electron emitters 34 are arranged in a line along the longitudinal direction of the cathode electrode 28, but the shape, the number and arrangement per pixel area, etc. of the electron emitter 34 are shown. It is not limited to this and can be variously modified.

In addition, the structure in which the gate electrodes 32 are positioned on the cathode electrodes 28 with the first insulating layer 30 therebetween has been described, but the gate electrodes 32 have the first insulating layer therebetween. A structure located below the field 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 36, which is a third electrode, is formed on the gate electrodes 32 and the first insulating layer 30. A second insulating layer 38 is positioned below the focusing electrode 36 to insulate the gate electrodes 32 and the focusing electrode 36, and passes the electron beam through the focusing electrode 36 and the second insulating layer 38. Openings 361 and 381 are provided.

The focusing electrode 36 may form one opening for each electron emission unit 34 to focus electrons emitted from each electron emission unit 34, and one opening 361 may be formed for each unit pixel. The electrons emitted from one unit pixel may be collectively focused. The figure shows the second case.

Next, on one surface of the second substrate 12 opposite to the first substrate 10, the fluorescent layers 14, for example, the red, green, and blue fluorescent layers 14R, 14G, and 14B are each other. It is formed at arbitrary intervals, and a black layer 16 is formed between the fluorescent layers 14 to improve the contrast of the screen.

An anode electrode 18 made of a metal film such as aluminum (Al) is formed on the fluorescent layer 14 and the black layer 16. The anode electrode 18 receives the high voltage necessary for accelerating the electron beam from the outside to maintain the fluorescent layer 14 in a high potential state, and visible light emitted toward the first substrate 10 of the visible light emitted from the fluorescent layer 14. 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 which case the anode electrode is positioned on one surface of the fluorescent layer 14 and the black layer 16 facing the second substrate 12. Moreover, the structure which forms simultaneously the above-mentioned transparent conductive film and a metal film as an anode electrode is also possible.

The spacer 20 positioned between the first substrate 10 and the second substrate 12 is made of a high resistance body as described above, and faces toward the first substrate 10 (the first substrate ( A lower layer 22 positioned on the side closer to 10) and an upper layer 24 positioned on the side facing the second substrate 12 (the side closer to the second substrate 12). In this case, the lower layer 22 and the upper layer 24 are formed of materials having different specific resistances.

The electron emission display device having the above configuration is driven by supplying a predetermined voltage to the cathode electrodes 28, the gate electrodes 32, the focusing electrode 36 and the anode electrode 18 from the outside.

For example, any one of the cathode electrodes 28 and the gate electrodes 32 may receive a scan driving voltage to serve as scan electrodes, and the other electrodes may receive a data driving voltage to serve as data electrodes. In addition, the focusing electrode 36 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 18 is a voltage necessary for accelerating the electron beam, for example, several hundred to several thousand V. DC voltage of is applied.

As a result, an electric field is formed around the electron emission part 34 in the unit pixels in which the voltage difference between the cathode electrode 28 and the gate electrode 32 is greater than or equal to a threshold, and electrons are emitted therefrom. The emitted electrons are focused through the opening 361 of the focusing electrode 36 to the center of the electron beam bundle, and are attracted to the fluorescent layer 14 of the corresponding unit pixel by being attracted by the high voltage applied to the anode electrode 18. It emits light.

Despite the action of the focusing electrode 36 during the driving process, electrons are emitted to the periphery of the electron beam bundle, some of these electrons collide with the spacer 20, and the spacer 20 is charged. Therefore, distortion occurs in the electron beam trajectory around the spacer 20 due to the influence of the charged spacer 20. At this time, since the spacer 20 of the present embodiment forms the lower layer 22 and the upper layer 24 with materials having different specific resistances, the equipotential lines are deformed to adjust and correct the electron beam trajectory that is distorted by charging. It is possible to minimize electron beam distortion around 20.

5 is a partial cross-sectional view of a surface conduction emission type electron emission display device according to an embodiment of the present invention. Since the configuration of the light emitting unit and the spacer provided on the second substrate is the same as that of the field emission array type electron emission display device described above, only the configuration of the electron emission device will be described here briefly.

Referring to the drawings, the first electrode 40 and the second electrode 42 are spaced apart from each other on each of the unit pixels on the first substrate 10, and the first electrode 40 and the second electrode 42 are respectively positioned on the first substrate 40. The first conductive thin film 44 and the second conductive thin film 46 are located close to each other. An electron emission portion 48 is formed between the first conductive thin film 44 and the second conductive thin film 46, and the electron emission portion 48 is formed through the first thin films 44 and 46. 40 is electrically connected to the second electrode 42.

The first electrode 40 and the second electrode 42 may be formed of various conductive materials. The first conductive thin film 44 and the second conductive thin film 46 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 part 48 may be formed of fine cracks provided between the first conductive thin film 44 and the second conductive thin film 46, or may be formed of a carbon-based material film. In the second case, the electron emitter 48 is formed of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbon, fullerene (C ₆₀ ), silicon nanowires and the like as in the field emission array (FEA) type described above. Combinations thereof.

In the above structure, when a voltage is applied to each of the first electrode 40 and the second electrode 42, the surface of the electron emission part 48 is formed through the first conductive film 44 and the second conductive film 46. 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 18 and collide with the corresponding fluorescent layer 14. To emit light.

During the driving process, the electrons are spread toward the second substrate 12 so that some of the electrons collide with the surface of the spacer 20, but the spacer of the present embodiment has a lower layer 22 and an upper layer having different resistivities. Since the equipotential lines are adjusted by the action of (24), distortion of the electron beam is not caused around the spacer 20.

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 according to the present invention includes a spacer having two or more layers formed of materials having different specific resistances, so that even if electrons emitted from the electron emission portion collide with the surface of the spacer to be charged, they are equipotential. It is possible to adjust the electron beam trajectory by applying strain to the line. Therefore, accurate color expression is possible around the spacer, and the display position of the spacer is not visible on the screen, thereby achieving excellent display quality.

Claims (13)

A spacer for an electron emission display device provided between a first substrate and a second substrate constituting a vacuum container to support a compressive force applied to the vacuum container. For electron emission display devices having a certain height along the thickness direction of the first substrate and the second substrate, made of a high resistance body, divided into two or more layers in the height direction, and neighboring layers made of materials having different resistivities from each other. Spacer. The method according to claim 1, A lower layer positioned on the side facing the first substrate and an upper layer positioned on the side facing the second substrate, wherein the lower layer and the upper layer are formed of materials having different specific resistances, and the lower layer and the upper layer overlap each other. An integrated spacer for an electron emission display device. The method according to claim 2, An intermediate layer is further formed between the lower layer and the upper layer, and the intermediate layer is formed of a material having a specific resistance different from the lower layer and the upper layer. The method according to claim 3, And the lower layer and the upper layer are formed of a material having the same resistivity. The method according to claim 1, Each material forming at least two layers is arranged such that the resistivity increases or decreases sequentially. A first substrate and a second substrate disposed opposite to each other, an electron emitting device provided on the first substrate, the electron emitting device comprising a plurality of electron emitting elements, and a fluorescent layer provided on the second substrate and any one surface of the fluorescent layers A light emitting unit including an anode electrode positioned at the first substrate; a plurality of spacers positioned between the first substrate and the second substrate; The spacer has a predetermined height along the thickness direction of the first substrate and the second substrate and is made of a high resistance body, and is divided into two or more layers in the height direction, and neighboring layers are made of materials having different resistivities from each other. Electron emission indicator device. The method according to claim 6, And each material forming at least two layers of the spacer is arranged such that the resistivity sequentially increases or decreases. The method according to claim 6, Cathode electrodes in which the electron emission device is formed along one direction of the first substrate; Gate electrodes formed along a direction crossing the cathode electrodes with an insulating layer interposed therebetween; And electron emission portions electrically connected to the cathode electrode. The method according to claim 8, And the electron emission unit comprises at least one material selected from the group consisting of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, fullerenes (C ₆₀ ), and silicon nanowires. The method according to claim 8, And an electron collecting device, wherein the electron emitting device is insulated from the cathode electrodes and the gate electrodes and further comprises a focusing electrode positioned on the cathode electrodes and the gate electrodes. The method according to claim 6, First and second electrodes at which the electron emission devices are spaced apart from each other; First conductive thin films formed on the first electrodes; Second conductive thin films formed on the second electrodes and positioned adjacent to each of the first conductive thin films; And electron emission units provided between each of the first conductive thin film and the second conductive thin film. The method according to claim 11, An electron emission display device in which the electron emission section is made of fine cracks. The method according to claim 11, And the electron emission unit comprises at least one material selected from the group consisting of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, fullerenes (C ₆₀ ), and silicon nanowires.

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