KR20070041984A - Electron emission display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron emission display device that corrects light emission efficiency and luminance differences that may occur according to the color of a fluorescent layer. Electron emitters formed on the first substrate, driving electrodes for controlling electron emission of the electron emitters, and red (R) and green (G) formed on one surface of the second substrate facing the first substrate. ) And a blue (B) fluorescent layer. Here, the individual surface areas of the electron emission parts positioned corresponding to each of the red, green, and blue fluorescent layers are formed in inverse proportion to the respective luminous efficiency of the red, green, and blue fluorescent layers.

Electron emission, luminous efficiency, luminance, fluorescent layer, electron emission area, surface area

Description

Electron Emission Display Device {ELECTRON EMISSION DISPLAY DEVICE}

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

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

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

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

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

TECHNICAL FIELD The present invention relates to an electron emission display device, and more particularly, to an electron emission display device including red, green and blue fluorescent layers, and electron emission portions emitting electrons to emit the fluorescent layers.

In general, an electron emission element 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.

Among them, the FEA type electron emission device includes an electron emission unit and driving electrodes for controlling electron emission of the electron emission unit, and includes one cathode electrode and one gate electrode, and has a low work function as a material of the electron emission unit. Or a high aspect ratio material, such as molybdenum (Mo) or silicon (Si), with a sharp tip structure, or an electric field in vacuum using carbon-based materials such as carbon nanotubes and graphite and diamond-like carbon. By using the principle that the electron is easily emitted by.

On the other hand, the electron emission elements are formed 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 composed of a fluorescent layer and an anode electrode to emit electrons. A display device (electron emission display device) is constituted.

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

The electron emission display device displays the color required for the designated pixel by adjusting the amount of emission of each of the red, green, and blue fluorescent layers existing in each pixel region. The amount of light emitted from the red, green, and blue fluorescent layers is controlled by the amount of emitted electrons emitted from the electron emission unit.

On the other hand, the red, green, and blue fluorescent layers show different luminous efficiency and luminance even when they collide with the same amount of electrons due to the properties of the constituent materials. For example, in order to display white color on one pixel, the red, green, and blue phosphor layers emit light at the same ratio. To this end, when the same amount of electrons collide with each phosphor, the emission efficiency and luminance difference according to the color are different. There is a problem that white is not displayed on a pixel that is set to display white.

This causes the screen display quality of the electron emission display device to deteriorate. To this end, a method of controlling the amount of electron emission for each phosphor in terms of a driving circuit in order to correct a difference in luminous efficiency and luminance of phosphors for each color is conventionally used. Is being presented. However, this causes a problem of complicating the driving circuit.

Accordingly, an object of the present invention is to solve the above problems, and an object of the present invention is to correct a difference in luminous efficiency and luminance generated according to phosphor color to improve display quality of a screen and to simplify electron driving. It is to provide a display device.

In order to achieve the above object, an electron emission device according to an embodiment of the present invention includes a first substrate and a second substrate disposed opposite to each other, electron emission portions formed on the first substrate, and electron emission of the electron emission portions. And an red (R), green (G), and blue (B) fluorescent layer formed on one surface of the second substrate facing the first substrate of the second substrate. . Here, the individual surface areas of the electron emission parts positioned corresponding to each of the red, green, and blue fluorescent layers are formed in inverse proportion to the respective luminous efficiency of the red, green, and blue fluorescent layers.

In addition, the luminous efficiency of each of the red, green, and blue fluorescent layers is denoted by E _R , E _G , and E _B , and the respective surface areas of the electron emission portions corresponding to the red, green, and blue fluorescent layers are denoted by S _R , S _G , and. when La S _B, the electron emission display device according to the invention satisfy the following conditions.

E _G > E _R > E _B ... (1)

S _B > S _R > S _G ... (2)

In addition, in the present invention, the red and blue fluorescent layers may be formed of an oxide compound, and the green fluorescent layer may be formed of a sulfide compound. In this case, S _R , S _G and S _B may satisfy 2: 1: 6.

In addition, the present invention can be applied not only to the field emission array (FEA) type but also to the surface conduction emission (SCE) 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 of an electron emission display device according to a first embodiment of the present invention, FIG. 2 is a partial plan view of an electron emission display device according to a first embodiment of the present invention, and FIG. A partial plan view of an electron emission display device according to an embodiment.

1 and 2, an electron emission display device according to an exemplary embodiment of the present invention includes a first substrate 2 and a second substrate 4 which are disposed to face each other in parallel to each other with an inner space interposed therebetween. Among these substrates, the first substrate 2 is provided with a configuration for emitting electrons, and the second substrate 4 is provided with a configuration for emitting visible light by electrons to perform any light emission or display.

More specifically, the cathode electrodes 6 are formed on the first substrate 2 in a stripe pattern along one direction (y-axis direction in FIG. 2) of the first substrate 2, and cover the cathode electrodes 6. In addition, the insulating layer 8 is formed on the entire first substrate 2. Gate electrodes 10 are formed on the insulating layer 8 in a stripe pattern along a direction orthogonal to the cathode electrode 6 (the x-axis direction in FIG. 2).

The cathode electrode 6 and the gate electrode 10 function as drive electrodes for generating a potential difference to control electron emission.

Further, in the present embodiment, at least one electron emission part 12 is formed over the cathode electrode 6 at each intersection region of the cathode electrode 6 and the gate electrode 10, and the insulating layer 8 and the gate electrode 10 are formed. In FIG. 2, openings 81 and 101 corresponding to the electron emission parts 12 are formed to expose the electron emission parts 12 on the first substrate 2.

The electron emission unit 12 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 (nm) size material. Preferred materials for use as the electron emitter 12 include carbon nanotubes, graphite, graphite nanofibers, diamond, diamond-like carbon, fullerene (C ₆₀ ), silicon nanowires, and combinations thereof.

Meanwhile, the structure in which the gate electrode 10 is positioned above the cathode electrode 6 with the insulating layer 8 interposed therebetween has been described. In the opposite case, that is, the structure in which the cathode electrode is positioned above the gate electrode. It is also possible. In this structure, the electron emission part may be formed on the insulating layer in contact with one side of the cathode electrode.

Next, a black layer 16 is formed on one surface of the second substrate 4 facing the first substrate 2 together with the fluorescent layer 14 to improve contrast of the screen. The fluorescent layer 14 is composed of a red fluorescent layer 14R, a green fluorescent layer 14G, and a blue fluorescent layer 14B for each pixel region. An anode electrode 18 made of a metal film such as aluminum is formed on one surface of the fluorescent layer 14 and the black layer 16.

The anode electrode 18 receives a high voltage necessary for accelerating the electron beam from the outside and increases the brightness of the screen by reflecting the visible light emitted toward the first substrate 2 of the visible light emitted from the fluorescent layer 14.

Meanwhile, the anode electrode 18 may be formed of a transparent conductive film such as indium tin oxide (ITO) instead of a metal film. In this case, the anode 18 may be disposed on one surface of the fluorescent layer 14 and the black layer 16 facing the second substrate 4, and may be formed in plural in a predetermined pattern.

In addition, a plurality of spacers 20 are provided between the first substrate 2 and the second substrate 4 to maintain a constant gap between the substrates 2 and 4.

In the electron emission display device having the above structure, the present invention forms the individual surface areas of the electron emission portions differently positioned corresponding to the red, green, and blue fluorescent layers 14R, G, and B, respectively.

That is, in order to correct the difference in luminous efficiency according to the color of the fluorescent layer, the present invention is applied to the individual surface area S _R of the electron emitting part 12R corresponding to the red fluorescent layer 14R and the green fluorescent layer 14G. The individual surface area S _G of the corresponding electron emitting portion 12G and the individual surface area S _B of the electron emitting portion 12B corresponding to the blue fluorescent layer 14B are formed in inverse proportion to the luminous efficiency of each fluorescent layer. .

Although the luminous efficiency of the fluorescent layer 14 varies depending on the constituent material, in general, the luminous efficiency (E _G ) of the green fluorescent layer 14G is the highest, followed by the luminous efficiency (E) of the red fluorescent layer 14R. _R ) is high, and the luminous efficiency (E _B ) of the blue fluorescent layer 14B is the lowest. (E _G > E _R > E _B ) In one example, the red fluorescent layer is an oxide such as Y ₂ O ₃ : Eu. ), The blue phosphor layer is made of an oxide-based compound such as Y ₂ SiO ₅ : Ce, and the green phosphor layer may be made of a sulfide compound such as ZnS: Cu.

The difference in luminous efficiency according to the color of the fluorescent layer can be solved by controlling the amount of electrons colliding with the fluorescent layer. That is, in the fluorescent layer having high luminous efficiency, less electrons collide with the fluorescent layer, and in the fluorescent layer having low luminous efficiency, more electrons collide with the fluorescent layer.

The control of the electron emission amount may be performed by adjusting the surface area of the electron emission parts. That is, since the electron emission amount is proportional to the surface area of the electron emission parts, the surface area of the electron emission part may be increased to increase the electron emission amount, and the surface area of the electron emission part may be reduced to reduce the electron emission amount.

Here, the surface area of the electron emission part means the area of the electron emission part exposed to the internal space of the vacuum, and in this embodiment, the area of the upper surface facing the second substrate 4 and the area of the side surface formed along the circumference of the electron emission part Includes all of them.

Based on this principle, as shown in FIGS. 1 and 2, the present invention maximizes the individual surface area S _B of the electron emission part 12B emitting the blue fluorescent layer 14B having the lowest luminous efficiency. Then, the individual surface area S _G of the electron emitting portion 12G which emits the green fluorescent layer 14G having the highest luminous efficiency is minimized. (S _B > S _R > S _G )

In particular, when the red and blue fluorescent layers 14R and B are made of an oxide compound, and the green fluorescent layer 14G is made of a sulfide compound, the red fluorescent layer 14R and green fluorescent material are The ratio of the luminous efficiency of the layer 14G and the blue fluorescent layer 14B may be 3: 6: 1. At this time, S _R , S _G and S _B may be 2: 1: 6. This ratio is because the same ratio is established by multiplying the emission efficiency ratio (E _R , E _G , E _B ) of each color by the individual surface area ratio (S _R , S _G , S _B ) of the electron emission part according to each color. . That is, E _R x S _R = E _G x S _G = E _B x S _B = 6 holds.

In FIG. 2, the electron emitters 12 are formed in a circular shape, and in FIG. 3, the electron emitters 13 are formed in a quadrangle, and the arrangement is formed in a line along the length direction of the cathode electrode 6. have. However, the planar shape of the electron emitter and the number and arrangement form per pixel area are not limited to the illustrated example, and if the ratio of the individual surface area according to the color of the fluorescent layer is established, the shape, number and arrangement may vary. Can be.

While the present invention has been described by applying the field emission array (FEA) type electron emission display device, the present invention can be applied not only to the field emission array (FEA) type but also to the surface conduction emission (SCE) type.

4 and 5 are partial cross-sectional views and partial plan views of an electron emission display device according to a third embodiment of the present invention, showing a surface conduction emission (SCE) type electron emission display device to which the present invention is applied. The electron emission display device according to the present exemplary embodiment has the same configuration as the first exemplary embodiment described above except for a structure for electron emission provided on the first substrate.

Referring to the drawings, the first electrode 34 and the second electrode 36 are disposed on the first substrate 32 at predetermined intervals, and the surfaces of the first electrode 34 and the second electrode 36 are respectively surfaced. The first conductive thin film 38 and the second conductive thin film 40 are formed to cover the portions of the first conductive thin film 38 and to be close to each other. An electron emission portion 42 is formed between the first conductive thin film 38 and the second conductive thin film 40 to connect the conductive thin films, and the electron emission portion 42 is formed of the conductive thin films 38. It is electrically connected to the first electrode 34 and the second electrode 36 through 40.

Here, the electron emission part 42 is formed in inverse proportion to the luminous efficiency of the fluorescent layer 44 as in the first embodiment described above. That is, as shown in Figs. 4 and 5, the individual surface area of the electron emitting portion 42B corresponding to the blue fluorescent layer 44B is formed largest, and then the electrons corresponding to the red fluorescent layer 44R are formed. The individual surface area of the emitter 42R is large, and the smallest surface area of the electron emitter 42G corresponding to the green fluorescent layer 44G is formed.

In particular, in the present embodiment, the red and blue fluorescent layers 44R and B may be formed of an oxide compound, and the green fluorescent layer 44G may be formed of a sulfide compound, in which case red fluorescent light is emitted. Individual surface area of electron emitting portion 42R corresponding to layer 44R, Individual surface area of electron emitting portion 42G corresponding to green fluorescent layer 44G and electron emitting portion 42B corresponding to blue fluorescent layer 44B The ratio of the individual surface areas of) can satisfy 2: 1: 6.

In the above-described structure, various materials having conductivity may be used for the first electrode 34 and the second electrode 36, and the first conductive thin film 38 and the second conductive thin film 40 may be nickel (Ni). And a fine particle thin film using a conductive material such as gold (Au), platinum (Pt), and palladium (Pd).

The electron emitting portion 42 is preferably formed of graphite carbon, a carbon compound, or the like. In addition, the electron emission part 42 may be formed of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, fullerenes (C ₆₀ ), silicon nanowires, and combinations thereof as in the first embodiment. Can be.

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 present invention adjusts the surface area of the electron emission part corresponding to the fluorescent layer, thereby correcting the luminous efficiency and luminance difference that may appear according to the color of the fluorescent layer, thereby improving the display quality of the screen, and driving circuit There is no need to correct this in terms of simplification of the drive circuit.

Claims (12)

A first substrate and a second substrate disposed to face each other; Electron emission parts formed on the first substrate; Drive electrodes for controlling electron emission of the electron emission parts; A red (R), green (G), and blue (B) fluorescent layer formed on one surface of the second substrate facing the first substrate, And an individual surface area of the electron emission portions positioned corresponding to each of the red, green, and blue fluorescent layers is formed in inverse proportion to the respective luminous efficiency of the red, green, and blue fluorescent layers. The method of claim 1, The respective luminous efficiencies of the red, green, and blue fluorescent layers are E _R , E _G , E _B , and the respective surface areas of the electron emission portions corresponding to the red, green, and blue fluorescent layers are S _R , S _G , S _{B, respectively.} An electron emission display device satisfying the following conditions simultaneously. E _G > E _R > E _B ... (1) S _B > S _R > S _G ... (2) The method of claim 2, An electron emission display device wherein E _R , E _G , E _B , S _R , S _G and S _B satisfy the following conditions. E _R × S _R = E _G × S _G = E _B × S _B The method of claim 2, And the red and blue phosphor layers are made of an oxide compound, and the green phosphor layer is made of a sulfide compound. The method of claim 3, An electron emission display device wherein S _R , S _G and S _B satisfy 2: 1: 6. A first substrate and a second substrate disposed to face each other; Cathode electrodes and gate electrodes disposed on the first substrate so as to cross each other while being insulated from each other; Electron emission parts connected to the cathode electrodes; A red (R), green (G), and blue (B) fluorescent layer formed on one surface of the second substrate facing the first substrate, An electron emission display device in which the individual surface area of the electron emission portion and the luminous efficiency of the fluorescent layer satisfy the following conditions. E _G > E _R > E _B ... (1) S _B > S _R > S _G ... (2) Here, E _R , E _G and E _B represent the luminous efficiency of the red fluorescent layer, the green fluorescent layer and the blue fluorescent layer, respectively, and S _R , S _G and S _B are the red fluorescent layer, the green fluorescent layer and the blue fluorescent layer, respectively. Denotes the individual surface area of the electron emitting portion corresponding to. The method of claim 6, The red and blue fluorescent layer is made of an oxide compound, the green fluorescent layer is made of a sulfide compound, An electron emission display device wherein S _R , S _G and S _B satisfy 2: 1: 6. The method of claim 6, The electron emission display device of which the planar shape of the electron emission unit is circular. The method of claim 6, An electron emission display device wherein the planar shape of the electron emission section is polygonal. The method according to claim 1 or 6, 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. A first substrate and a second substrate disposed to face each other; First and second electrodes spaced apart from each other on the first substrate; A first conductive thin film and a second conductive thin film formed so as to be close to each other while covering a portion of the surface of the first electrode and the second electrode; Electron emission parts formed between the first conductive thin film and the second conductive thin film; And A red (R), green (G), and blue (B) fluorescent layer formed on one surface of the second substrate facing the first substrate, An electron emission display device in which the individual surface area of the electron emission portion and the luminous efficiency of the fluorescent layer satisfy the following conditions. E _G > E _R > E _B ... (1) S _B > S _R > S _G ... (2) Here, E _R , E _G and E _B represent the light emission efficiencies of the red fluorescent layer, the green fluorescent layer and the blue fluorescent layer, respectively, and S _R , S _G and S _B are the red fluorescent layer, the green fluorescent layer and the blue fluorescent layer, respectively. The individual surface area of the electron emitting portion corresponding to the layer is shown. The method of claim 11, The red and blue fluorescent layer is made of an oxide compound, the green fluorescent layer is made of a sulfide compound, An electron emission display device wherein S _R , S _G and S _B satisfy 2: 1: 6.

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