KR20070046655A - Electron emission device and electron emission display device using the same - Google Patents

Abstract

The present invention relates to an electron emission device and an electron emission display device using the same that can enhance the emission fidelity of the fluorescent layer and the luminance uniformity between the fluorescent layers. The electron emission device according to the present invention includes a substrate and a cathode electrode formed on the substrate. And electron emission portions electrically connected to the cathode electrode, and gate electrodes formed on the cathode electrodes and insulated from the cathode electrode and formed in a direction crossing the cathode electrode, wherein the cathode electrode and the gate electrode are intersected with each other. Each of the plurality of electron emitters having different sizes is located.

Electron emission unit, cathode electrode, insulating layer, gate electrode, focusing electrode, fluorescent layer, anode electrode

Description

ELECTRON EMISSION DEVICE AND ELECTRON EMISSION DISPLAY DEVICE USING 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 partially enlarged plan view of the electron emitting device illustrated in FIG. 1.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron emission device, and more particularly, to an electron emission device having an improved shape of an opening of an electron emission portion and a gate electrode in order to increase light emission uniformity of a fluorescent layer, and a display device using the same.

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 emission device using the cold cathode may be a field emitter array (FEA) type, a surface conduction emission type (SCE) type, a metal insulating layer, a metal insulating layer, or a metal insulating layer. Metal (MIM) type and Metal-Insulator-Semiconductor (MIS) type are known.

Among these, the FEA type electron emission device has an electron emission portion and a driving electrode for controlling electron emission of the electron emission portion, and includes one cathode electrode and one gate electrode, and has a low work function as a constituent material of the electron emission portion. In addition, using a material having a high aspect ratio, for example, carbon nanotubes and carbon-based materials such as graphite and diamond-like carbon, the principle that electrons are easily released by an electric field in vacuum is used.

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.

In a conventional FEA type electron emission display device, cathode electrodes, an insulating layer, and gate electrodes are sequentially formed on a first substrate, and openings are formed in the gate electrode and the insulating layer to expose a portion of the surface of the cathode electrode, and then into the opening. The electron emission part is formed on the cathode electrode, and the red, green, and blue fluorescent layers and the anode electrode are formed on one surface of the second substrate.

The electron emission portions and the gate electrode openings that open them are generally arranged in a line along the length direction of one electrode for each unit pixel where the cathode electrode and the gate electrode intersect, and the electron emission portions are all the same size regardless of the position. The gate electrode openings are also formed in the same size.

However, the electron emission display device having the above-described configuration applies an driving voltage to the cathode electrodes and the gate electrodes to emit electrons from the electron emission unit by using the voltage difference between the two electrodes per unit pixel, and thus reaches the fluorescent layer. The silver forms a different shape from the fluorescent layer.

In other words, a large amount of electrons collide with each other in one fluorescent layer to produce a portion having high luminous efficiency and a portion thereof, which causes a problem in that the emission fidelity of the fluorescent layer and luminance uniformity between the fluorescent layers are deteriorated.

Accordingly, an object of the present invention is to solve the above problems, and an object of the present invention is to ensure that electrons emitted from an electron emission unit emit light uniformly on each part of the fluorescent layer, so that light emission fidelity of the fluorescent layer and luminance uniformity between the fluorescent layers are uniform. To provide an electron emission device and an electron emission display device using the same that can increase the.

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

A substrate, cathode electrodes formed on the substrate, electron emitters electrically connected to the cathode electrode, and gate electrodes formed along the direction intersecting the cathode electrode and insulated from the cathode electrode on the cathode electrodes; The present invention provides an electron emitting device in which a plurality of electron emitters having different sizes are located at each intersection region of a cathode electrode and a gate electrode.

The gate electrodes form openings that expose respective electron emitters, and the openings are formed in different sizes according to the size of the electron emitters.

Electron emitters positioned at the periphery of the crossing area may be formed to have a larger size than electron emitters located at the center of the crossing area. For example, the electron emission parts may be disposed in a line along the length direction of one of the cathode electrode and the gate electrode, and the outermost electron emission parts along the length direction may be larger than the electron emission parts located at the center part. It can be formed in size.

The focusing electrode may be positioned to be insulated from the gate electrodes on the gate electrodes, and form an opening in each of the crossing regions. In particular, the focusing electrode may form an opening having semicircular ends at both ends.

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

A first substrate and a second substrate disposed opposite to each other, cathode electrodes formed on the first substrate, electron emission parts electrically connected to the cathode electrode, and insulated from the cathode electrode on the cathode electrodes, Gate electrodes formed along the crossing direction, fluorescent layers formed on one surface of the second substrate, and anode electrodes formed on one surface of the fluorescent layers, and the sizes are different for each intersection region of the cathode electrode and the gate electrode. Provided is an electron emission indicator device in which a plurality of other electron emitters are located.

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, respectively, and FIG.

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.

An intersection area between the cathode electrodes 14 and the gate electrodes 18 forms a unit pixel, and electron emission parts 20 are formed in each unit pixel above 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, so that the electron emission parts 20 are formed on the first substrate 10. To be exposed.

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 carbon nanotubes (CNT), graphite, graphite nanofibers, diamonds, diamond-like carbons (DLC), C ₆₀ , silicon nanowires, and combinations thereof. Printing, direct growth, sputtering or chemical vapor deposition (CVD) can be applied.

In the present exemplary embodiment, the electron emission portions 20 having different sizes are formed together in each unit pixel so as to control the amount of electron emission for each position, and the opening 181 of the gate electrode 18 is adapted to the size of the electron emission portions 20. ) Are also formed in different sizes. That is, since the electron emission amount is proportional to the size of the electron emission unit 20, an electron emission unit having a large size is formed at a position to increase the electron emission amount.

The electron emission parts 20 may be positioned in one line along the length direction of the cathode electrode 14 and the gate electrode 18, for example, the cathode electrode 14, and the length of the cathode electrode 14 may be reduced. In order to increase the electron emission amount in the upper and lower peripheral portions of each unit pixel along the direction, as shown in the drawing, the first electron emitting unit 201 positioned in the upper and lower peripheral portions of each unit pixel is positioned in the center of the unit pixel. It is formed larger than the discharge portions (202).

In this case, the distance d between the electron emission unit 20 and the gate electrode 18 measured along the surface direction of the first substrate 10 may be the same regardless of the size of the electron emission unit 20. Is done.

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 provided. In the present embodiment, the openings 221 and 241 are formed for each unit pixel so that the focusing electrode 22 comprehensively focuses electrons emitted from one unit pixel.

At this time, the focusing electrode 22 forms a semicircular end of its opening 221 in response to the first electron emission parts 201 positioned in the outermost direction along the longitudinal direction of the cathode electrode 14 to the electron beam path. The focusing electrode 22 is to be as close as possible. As a result, when electrons are emitted from the first electron emission unit 201, the electrons may be efficiently focused by the focusing electrode 22 to suppress excessive beam spreading.

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. The fluorescent layer 26 is disposed so that one fluorescent layer 26 corresponds to each unit pixel 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.

On the other hand, the anode electrode may be made of a transparent conductive film such as indium tin oxide (ITO) rather than a metal film. In this case, the anode is positioned 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.

In addition, a plurality of spacers 32 (see FIG. 2) 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.

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 are attracted to the fluorescent layer 26 of the corresponding unit pixel by being attracted by the high voltage applied to the anode electrode 30. It emits light.

In the driving process described above, the electron emission display device of the present exemplary embodiment can easily control the amount of electron emission for each location by disposing the electron emission units 201 and 202 having different sizes in one unit pixel. Therefore, when the electrons hit the fluorescent layer 26 to form an electron beam spot, the fluorescent layer 26 can be uniformly emitted, thereby increasing the emission fidelity of the fluorescent layer and increasing the luminance uniformity between the fluorescent layers. have.

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 such, the electron emission display device according to the present invention can easily control the amount of electron emission for each location by disposing electron emission parts having different sizes in one unit pixel. Accordingly, the electron emission display device according to the present invention can realize a high quality screen by increasing the emission fidelity of the fluorescent layer and the luminance uniformity between the fluorescent layers.

Claims (9)

A substrate; Cathode electrodes formed on the substrate; Electron emission parts electrically connected to the cathode electrode; And A gate electrode which is insulated from the cathode electrode on the cathode electrodes and formed along a direction crossing the cathode electrode, And a plurality of electron emitters having different sizes at each intersection region of the cathode electrode and the gate electrode. The method of claim 1, And the gate electrodes form openings that expose each of the electron emission portions, and the openings are formed in different sizes to match the size of the electron emission portion. The method of claim 1, And the electron emitting portions located at the periphery of the crossing area are formed to be larger in size than the electron emitting portions located at the center of the crossing area. The method of claim 3, The electron emission parts are positioned in a line along a length direction of one of the cathode electrode and the gate electrode, And the outermost electron emitting portions along the longitudinal direction are formed to be larger in size than the electron emitting portions located at the center portion. The method of claim 4, wherein And the gate electrodes form openings that expose the upper portion of each of the electron emission portions, and the distance between the electron emission portion and the gate electrode measured along the plane direction of the substrate is the same in all the electron emission portions. The method of claim 1, And a focusing electrode positioned above the gate electrodes and insulated from the gate electrodes, the focusing electrode forming one opening for each of the crossing regions. The method of claim 4, wherein And a focusing electrode positioned above the gate electrodes and insulated from the gate electrodes, the focusing electrode forming an opening having semicircular ends at each crossing area. The method of claim 1, 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, C ₆₀ and silicon nanowires. An electron emitting device according to any one of claims 1 to 8; Another substrate disposed to face the substrate; Red, green, and blue fluorescent layers formed on one surface of the other substrate; And An anode electrode formed on one surface of the fluorescent layers, And a fluorescent layer of one color corresponding to each of the fluorescent layers.

Images