KR20070041990A - Electron emission element and electron emission device having the same - Google Patents

Abstract

The present invention provides an electron emitting device capable of improving electron emission uniformity and electron beam focusing efficiency and an electron emitting device having the same.

The electron emission device according to the present invention is disposed in a direction orthogonal to an electrode including a first electrode and a second electrode formed separately from the first electrode, a first electrode, and a second electrode, and thus the first electrode and the second electrode. And a resistive layer connecting the electrodes, and an electron emission unit electrically connected to the electrodes.

Electron-emitting device, resistive layer, cathode, gate electrode, FEA

Description

ELECTRON EMISSION ELEMENT AND ELECTRON EMISSION DEVICE HAVING 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 and 3 are partial cross-sectional views of an electron emission display device according to an embodiment of the present invention.

4 is a partial plan view of an electron emission display device according to an embodiment of the present invention.

FIG. 5 is a view showing a light emitting state appearing in one pixel of an electron emission display device according to an embodiment of the present invention. FIG.

FIG. 6 is a diagram showing a light emission state appearing in one pixel of a conventional electron emission display device. FIG.

The present invention relates to an electron emitting device, and more particularly, to an electron emitting device and an electron emitting device having the same that can improve electron emission uniformity and electron beam focusing efficiency.

In general, an electron emission element is classified into a method using a hot cathode and a method using a cold cathode.

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

Among them, 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 work function as a material of the electron emission portion. materials with low functions or high aspect ratios, such as tip structures with a major tip made of molybdenum (Mo) or silicon (Si), or carbon nanotubes and graphite and diamond carbon Carbon-based materials are used to facilitate the release of electrons by an electric field in a vacuum.

On the other hand, the electron-emitting device is arranged in one substrate to form an electron emission device (electron emission device), the electron-emitting device is disposed opposite to another substrate having a fluorescent layer and an anode electrode on one surface to form a vacuum container An emission display device is configured.

In general, the electron-emitting device has a cathode electrode and a gate electrode sequentially formed in an intersecting direction with an insulating layer interposed therebetween, and openings are formed in the gate electrode and the insulating layer of the intersection region between the two electrodes, respectively. The electron emission portion is formed on the cathode electrode inward, and the electron emission portion is formed in the electron emission portion according to the voltage applied to the cathode electrode and the gate electrode.

When the electron emission devices form an array to form an electron emission device, a scan signal voltage is applied to one of the cathode electrode and the gate electrode, and a data signal voltage is applied to the other electrode, so that the cathode electrode and the gate electrode are applied. In electron-emitting devices whose inter-voltage difference is greater than or equal to a threshold, an electric field is formed around the electron-emitting portion, whereby electron emission is made.

When the electron emission device is combined with another substrate provided with a light emitting unit to form an electron emission display device, the electron emission display device is configured such that electrons emitted from the electron emission elements are accelerated to the corresponding fluorescent layer by an anode electrode to produce a electron emission display device. It will emit light or display.

However, in the electron emission device, as the cathode electrode and the gate electrode have internal resistance, a voltage drop may occur when a driving voltage such as a scan signal voltage or a data signal voltage is applied to each electrode.

In particular, when the cathode is formed of a transparent conductive material such as indium tin oxide (ITO) in consideration of the backside exposure for forming an electron emission part, the inside of the cathode is formed of a metal such as aluminum (Al) or silver (Ag). Since the resistance is large, the above problem may be further exacerbated.

As such, when a voltage drop occurs when the electron emission device is driven, a difference in electric field strength applied to the electron emission unit may be generated for each electron emission device when a driving voltage having the same value for all the electron emission devices is applied to the corresponding electrode. As a result, electron emission uniformity is lowered, and a display device having the electron emission device has a problem of deterioration in luminance characteristics.

In order to solve this problem, the conventional electron emission device applies a method of controlling the amount of current applied to each electron emission element by applying a resistive layer to the cathode electrode. In this case, the electron-emitting device is composed of, for example, two electrodes in which the cathode electrodes are separated from each other on the same plane, and the two electrodes are connected to each other by a resistive layer disposed in parallel thereto, and any one of the two electrodes Has an structure in which an electron emission portion is formed on an electrode of the electrode.

However, in the electron emission device, when a data signal voltage or a scan signal voltage is applied to the cathode, two voltages are applied to the two electrodes due to the resistive layer, and each electron emission element is driven around the electron emission element when the electron emission device is driven. The electric fields generated at the lateral planes have different intensities in the horizontal direction.

As such, when the intensity of the electric field generated around the electron emission unit is not uniform, beam spreading of electrons emitted from the electron emission unit occurs, and thus the electron beam focusing efficiency is lowered. There is a problem that secondary light emission occurs and the color reproducibility of the screen is lowered.

Accordingly, an object of the present invention is to provide an electron emission device capable of improving electron emission uniformity and electron beam focusing efficiency.

Another object of the present invention is to provide an electron emitting device having the electron emitting device.

In order to achieve the above object, the present invention provides an electrode including a first electrode and a second electrode formed separately from the first electrode, the first electrode and the second electrode are arranged in a direction orthogonal to the first electrode and the Provided is an electron emission device including a resistance layer connecting a second electrode and an electron emission portion electrically connected to the electrode.

In order to achieve the above object, the present invention provides a substrate, a direction formed orthogonal to the cathode electrode, the first electrode and the second electrode including a first electrode and a second electrode formed separately from the first electrode A gate electrode disposed on the cathode electrode with an insulating layer interposed therebetween and having a resistance layer connecting the first electrode and the second electrode, an electron emission portion electrically connected to the cathode electrode, and an opening corresponding to the electron emission portion; It provides an electron emitting device comprising a.

Here, the first electrode and the second electrode may be formed on the same plane, the second electrode may have an opening, the first electrode may be disposed into the opening, and the electron emission part may be formed on the first electrode.

In addition, resistance layers may be formed on both sides of the first electrode, respectively.

In addition, the resistive layer may be made of a material having a specific resistance of several kΩcm to several tens of kΩcm.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 to 4 are diagrams illustrating an electron emission display device according to an exemplary embodiment of the present invention, in which FIG. 1 is a partially exploded perspective view, FIGS. 2 and 3 are partial cross-sectional views, and FIG. 4 is a partial plan view.

1 to 4, the electron emission display device includes a first substrate 10 and a second substrate 20 that are disposed to face each other in parallel with each other at predetermined intervals. Sealing members (not shown) are disposed at edges of the first substrate 10 and the second substrate 20 to bond the two substrates, and the first substrate 10 and the second substrate 20 and the sealing member are vacuumed. Construct a container.

On the opposite surface of the first substrate 10 to the second substrate 20, an electron emission unit 100 that emits electrons toward the second substrate 20 is provided, and the first substrate of the second substrate 20 is provided. On the opposite side to (10), there is provided a light emitting unit 200 that emits visible light by the electrons to perform any light emission or display.

More specifically, first, the cathode electrodes 110 for controlling electron emission are formed on the first substrate 10 in a stripe pattern along one direction (y-axis direction in the drawing) of the first substrate 10. The cathode electrode 110 includes a first electrode 112 and a second electrode 114 that is disposed separately from the first electrode 112, and the second electrode 114 is disposed with the first electrode 112. It is provided with an opening 114a. Here, the opening 114a of the second electrode 114 substantially corresponds to the intersection area of the gate electrode 130 and the cathode electrode 110, which will be described later. In addition, the first electrode 112 and the second electrode 114 are connected by the resistance layer 116, and the electron emission unit 140 is formed on the first electrode 112.

In the present embodiment, both the first electrode 112 and the second electrode 114 may be made of a transparent conductive material such as ITO and IZO, and the first electrode 112 may be made of a transparent conductive material such as ITO and IZO. The second electrode 114 is a conductive material having better electrical conductivity than the first electrode 112, for example, chromium (Cr), molybdenum (Mo), niobium (Nb), nickel (Ni), and tungsten (W). It may be made of a metal such as tantalum (Ta), and the resistive layer 116 may be formed of a material having a specific resistance of several kΩcm to several tens of kΩcm, for example, amorphous silicon.

The electron emission unit 140 is formed of materials that emit electrons when an electric field is applied in a vacuum, such as a carbon-based material or a nanometer-sized material. The electron emission unit 140 may be formed of any one of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, C ₆₀ (fullerenes), silicon nanowires, or a combination thereof. Printing, direct growth, chemical vapor deposition or sputtering can be applied.

In the present embodiment, the first electrode 112 and the second electrode 114 are formed on the same plane, and the resistance layer 116 is perpendicular to the first electrode 112 and the second electrode 114. The electrodes are disposed on both sides of the first electrode 112 to contact the first electrode 111 and the second electrode 112, respectively.

In the drawing, the resistance layer 118 spans the first electrode 112 and the second electrode 114 to be in contact with the upper sides and edges of the first electrode 112 and the second electrode 114. The resistance layer 118 may be formed by contacting only the sides of the first electrode 112 and the second electrode 114. At this time, the former case has a large contact area and is advantageous in contact characteristics as compared with the latter case.

In the drawing, five electron emission units 140 having a circular plane shape are arranged per five electrodes of the first electrode 112 along the length direction of the cathode electrode 110, but the planar shape of the electron emission unit 140 is shown. The number and the like are not limited to the illustrated example and can be variously modified.

In addition, in the drawing, the case where the resistance layer 116 connects the first electrode 112 and the second electrode 114 in one pattern on each side of the first electrode 112 is illustrated. The number of patterns is not limited to the illustrated example and can be variously modified.

Meanwhile, the first insulating layer 120 is formed on the entirety of the first substrate 10 on the cathode electrode 110, and the direction orthogonal to the cathode electrode 110 on the first insulating layer 120 (the x-axis in the drawing). Direction), the gate electrodes 130 are formed in a stripe pattern.

The first insulating layer 120 and the gate electrode 130 are provided with openings 120a and 130a corresponding to the electron emission units 140, respectively, and the first substrate 10 is provided through the openings 120a and 130a. The electron emitter 140 is exposed upward.

Although the shape of the openings 120a and 130a of the first insulating layer 120 and the gate electrode 130 is circular in plan view, the shape of the openings 120a and 130a is not limited to the illustrated example. Various modifications are possible.

In the above-described electron emission display device, the first electrode 112, the second electrode 114, the resistance layer 116, the electron emission unit 140, and the first insulating layer 120 of one cathode electrode 110 are provided. And the gate electrode 130 form an electron emission device, and the electron emission device forms an array on the first substrate 10 to form an electron emission device.

In addition, in the electron emission display device, the second insulating layer 150 and the focusing electrode 160 may be sequentially formed on the gate electrode 130. In this case, the second insulating layer 150 and the focusing electrode 160 are also provided with openings 150a and 160a for passing electron beams. For example, the openings 150a and 160a may be provided per electron emission element to focus the electrodes. 160 allows comprehensive collection of electrons emitted from one electron emitting device. At this time, since the focusing electrode 160 exhibits an excellent focusing effect as the height difference from the electron emission unit 150 increases, forming the thickness of the second insulating layer 150 larger than the thickness of the first insulating layer 120. desirable.

Although not specifically illustrated in the drawing, the focusing electrode 160 may be formed as one in the entirety of the first substrate 10 or may be formed in plurality in a predetermined pattern.

In addition, the focusing electrode 160 may be formed of a conductive film coated on the second insulating layer 150 or may be formed of a metal plate having an opening 160a.

Next, a fluorescent layer 210 and a black layer 220 are formed on one surface of the second substrate 20 facing the first substrate 10, and aluminum and the fluorescent layer 210 and the black layer 220 are formed on the surface of the second substrate 20. An anode electrode 230 made of the same metal is formed. The anode electrode 230 receives a high voltage necessary for accelerating the electron beam from the outside, and reflects the visible light emitted toward the first substrate 10 among the visible light emitted from the fluorescent layer 210 to the second substrate 20 side of the screen. It increases the brightness.

Meanwhile, the anode electrode 230 may be formed on one surface of the fluorescent layer 210 and the black layer 220 facing the second substrate 20, and in this case, may transmit visible light emitted from the fluorescent layer 210. So that the anode electrode is made of a transparent conductive material such as ITO.

On the other hand, on the second substrate 20, both the anode electrode of the transparent conductive material and the metal thin film for increasing the luminance by the reflection effect may be formed.

The fluorescent layer 210 may be disposed in a one-to-one correspondence with the pixel area defined on the first substrate 10 or may be formed in a stripe pattern along the vertical direction (y-axis direction of the drawing) of the screen, and the black layer 220 It may be made of an opaque material such as silver chromium or chromium oxide.

In the above-described electron emission display device, the fluorescent layer 210 is formed corresponding to the electron emission element, wherein one fluorescent layer 210 and one electron emission element corresponding to each other form a substantial pixel of the electron emission display device. do.

Next, a plurality of spacers 300 are disposed between the first substrate 10 and the second substrate 20 to maintain a constant gap between the two substrates 10 and 20. In this case, the spacers 300 are disposed corresponding to the non-light emitting region where the black layer 220 is located.

In the electron emission display device configured as described above, for example, a positive voltage of several hundred to several thousand volts is applied to the anode electrode 230 and a scan signal voltage is applied to any one of the cathode electrode 110 and the gate electrode 130. At the same time, the data signal voltage is applied to the other electrode and driven.

Then, in the electron emission devices in which the voltage difference between the cathode electrode 110 and the gate electrode 130 is greater than or equal to the threshold, an electric field is formed around the electron emission unit 140, and electrons are emitted therefrom, and the emitted electrons are the anode electrode ( It is attracted by the high voltage applied to the 230 impinges on the fluorescent layer 210 and emits it.

In this process, since the amount of current applied to each electron emission element can be controlled by the resistive layer 116, the electron emission display device of the present embodiment achieves uniform electron emission for each electron emission element.

In addition, in the electron emission display device of the present exemplary embodiment, the resistive layer 116 is disposed in a direction orthogonal to the first electrode 112 and the second electrode 114 of the cathode electrode 110, and thus, the first electrode 112 and the first electrode may be disposed. Since the same voltage is applied to the two electrodes 114, the electric field generated around the electron emission portion of each electron emission element has a uniform intensity. As a result, beam spreading of the electrons emitted from the electron emission unit may be suppressed and secondary light emission may be minimized to improve color reproducibility.

Table 1 below shows red (R), green (G), and blue (B) in the electron emission display device (example) of the present invention and the conventional electron emission display device (comparative example). Color data (x, y) appearing in each pixel and color reproducibility compared to the NTSC (National Television System Committee) standard of the CRT (Cathod-Ray Tube). In contrast, it can be seen that secondary light emission is minimized, thereby improving color reproducibility.

Example Comparative example Color coordinates x y x y Enemy (R) 0.635 0.335 0.575 0.354 Rust (G) 0.275 0.605 0.287 0.524 Blue (B) 0.142 0.065 0.165 0.105 Color reproducibility 72.8% 44.7%

5 and 6 respectively show light emission states of one pixel of an electron emission display device of the present invention and a conventional electron emission display device, for example, a green (R) pixel, and the electron emission display device of the present invention. It can be seen that the color reproducibility is improved as compared with the conventional electron emission display device.

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, the electron emission device according to the present invention can prevent the voltage drop of the cathode electrode, thereby minimizing the difference in the amount of electrons emitted for each electron emission element, thereby improving the electron emission uniformity.

In addition, the electron emission device according to the present invention can improve the electron beam focusing efficiency by generating an electric field of uniform intensity around the electron emission portion for each electron emission element, thereby minimizing secondary light emission.

As a result, the electron emission display device having the electron emission device according to the present invention can improve the brightness and color reproducibility and can improve the display quality of the screen.

Claims (9)

An electrode including a first electrode and a second electrode formed separately from the first electrode; A resistance layer disposed in a direction orthogonal to the first electrode and the second electrode and connecting the first electrode and the second electrode; And An electron emission unit electrically connected to the electrode Electron emitting device comprising a. According to claim 1, And the first electrode and the second electrode are formed on the same plane. According to claim 1, The electron emission device of which the resistive layer is made of a material having a specific resistance of several kΩcm to several tens of kΩcm. Board; A cathode formed on the substrate, the cathode comprising a first electrode and a second electrode separated from the first electrode; A resistance layer disposed in a direction orthogonal to the first electrode and the second electrode and connecting the first electrode and the second electrode; An electron emission part electrically connected to the cathode electrode; A gate electrode having an opening corresponding to the electron emission part and formed on the cathode electrode with an insulating layer interposed therebetween; Electron emitting device comprising a. The method of claim 4, wherein And the first electrode and the second electrode are formed on the same plane. The method of claim 5, And the second electrode has an opening, the first electrode is disposed into the opening, and the electron emission portion is formed above the first electrode. The method of claim 6, And the resistance layer is formed on both sides of the first electrode, respectively. The method of claim 4, wherein And the resistive layer is made of a material having a specific resistance of several kΩcm to several tens of kΩcm. The method of claim 4, wherein And a focusing electrode insulated from said gate electrode and formed over said gate electrode.

Images