KR20070078900A - Electron emission device and electron emission display device using the same - Google Patents

Abstract

An electron emission device and an electron emission display device using the same are provided to improve display quality by enhancing the amount of emitting electrons of unit pixels and emission uniformity of phosphor layers. A plurality of cathode electrodes(14) are formed on a substrate. A plurality of gate electrodes(18) are positioned on the substrate and are isolated from the plurality of cathode electrodes. A plurality of electron emission units(20) are electrically connected with the plurality of cathode electrodes. Each of the cathode electrodes includes a main electrode(22) formed with a transparent conductive layer and an auxiliary electrode(24) positioned on one side of the main electrode. The auxiliary electrode is formed by laminating a molybdenum layer(241) and an aluminum layer(242). The molybdenum layer is laminated on the aluminum layer.

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 a first embodiment of the present invention.

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

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

The present invention relates to an electron emission device, and more particularly, to an electron emission device to which an auxiliary electrode is applied to reduce the line resistance of a driving electrode, and an electron emission 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-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 includes 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. The use of low or high aspect ratio materials, such as carbon nanotubes and carbon-based materials such as graphite and diamond-like carbon, takes advantage of the principle that electrons are easily released by an electric field in vacuum.

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 constituted.

The electron emission device has a plurality of driving electrodes for controlling the amount of emission current of the electron emission portions per unit pixel in addition to the electron emission portion, and the electron emission display device excites a fluorescent layer with electrons emitted from the electron emission portion to It emits light or displays.

In order to increase the size of the electron emission display device, it is essential to reduce the line resistance of the driving electrodes. When the driving electrode has a relatively large line resistance, a voltage drop occurs along the length direction of the driving electrode, and the amount of electron emission per unit pixel and the emission uniformity of the fluorescent layer decrease in this direction.

Accordingly, a method of reducing the line resistance of the driving electrode by forming an auxiliary electrode made of a metal material having a lower resistance than the driving electrode on one surface of the driving electrode has been proposed.

However, the auxiliary electrode should not have a chemical reaction such as a galvanic phenomenon at the interface in contact with the driving electrode, and exhibit selective etching characteristics with the driving electrode to prevent the driving electrode from being patterned together when the auxiliary electrode is etched. Careful choice of materials and structures is required.

Therefore, the present invention is to solve the above problems, an object of the present invention is to suppress the chemical reaction between the drive electrode and the auxiliary electrode, and to prevent the driving electrode is etched together when patterning the auxiliary electrode by etching An electron emitting device and an electron emitting display device using the same are provided.

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

A substrate, cathode electrodes formed on the substrate, gate electrodes insulated from the cathode electrodes, and electron emission portions electrically connected to the cathode electrodes, wherein each cathode electrode is made of a transparent conductive film. The present invention provides an electron emission device including a main electrode and an auxiliary electrode disposed on one surface of the main electrode and formed of a molybdenum layer and an aluminum layer laminated from the main electrode.

The auxiliary electrode may further include an additional molybdenum layer stacked on the aluminum layer.

The gate electrode may include a main electrode and an auxiliary electrode formed on one surface of the main electrode and formed of a molybdenum layer and an aluminum layer stacked from the main electrode. In this case, the main electrode may be made of a chromium layer, and the auxiliary electrode may further include an additional molybdenum layer stacked on the aluminum layer.

The electron emitting device may further include a focusing electrode that is insulated from the cathode and gate electrodes and positioned above the cathode and gate electrodes.

The focusing electrode may include a main electrode and an auxiliary electrode formed on one surface of the main electrode and formed of a molybdenum layer and an aluminum layer stacked from the main electrode. In this case, the main electrode may be made of a chromium layer, and the auxiliary electrode may further include an additional molybdenum layer stacked on the aluminum layer.

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

First and second substrates disposed opposite to each other, cathode electrodes formed on the first substrate, gate electrodes positioned to be insulated from the cathode electrodes, electron emission parts electrically connected to the cathode electrodes, and 2 includes a fluorescent layer located on one surface of the substrate, an anode formed on one surface of the fluorescent layers, each cathode electrode comprising a transparent conductive film, and a molybdenum from the main electrode located on one surface of the main electrode. An electron emission display device including an auxiliary electrode formed by laminating a layer and an aluminum layer is provided.

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 a first embodiment of the present invention, respectively.

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 constitutes one unit pixel, and electron emission parts 20 are formed in each unit pixel on the cathode electrode 14. . In addition, openings 161 and 181 (refer to FIG. 2) corresponding to the electron emission parts 20 are formed in the first insulating layer 16 and the gate electrodes 18 to form the electron emission parts 20 on the first substrate 10. To be exposed.

In the present embodiment, the cathode electrode 14 includes a main electrode 22 made of a transparent conductive film such as indium tin oxide (ITO), and an auxiliary electrode 24 formed on the main electrode 22. 24 has a structure in which the molybdenum layer 241 and the aluminum layer 242 are sequentially stacked from the main electrode 22.

The main electrode 22 is formed of a transparent conductive film such as ITO so as to apply a so-called backside exposure method that forms an electron emitting portion 20 by irradiating ultraviolet rays from the rear surface of the first substrate 10 to cure the electron emitting material. Is done.

The auxiliary electrode 24 allows the molybdenum layer 241 to contact the main electrode 22 instead of the aluminum layer 242 to prevent galvanic phenomenon that may occur between the main electrode 22 and the aluminum layer 242. Since the molybdenum layer 241 and the aluminum layer 242 may be etched with the same etchant, for example, a mixture of phosphoric acid, nitric acid, and acetic acid, the auxiliary electrode 24 may be simultaneously patterned with a single etchant.

At this time, the main electrode 22 is not etched in the etching liquid of the auxiliary electrode 24, and the cathode electrode 14 has the effect of reducing the line resistance by the auxiliary electrode 24 having higher conductivity than the main electrode 22. The auxiliary electrode 24 may be formed along the longitudinal direction of the main electrode 22 at both edges of the main electrode 22 or may be formed on the entire upper surface of the main electrode 22 except for the electron emission part 20 forming portion. In the drawings, the first case is illustrated.

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, for example, carbon nanotubes (CNT), graphite, graphite nanofibers, diamonds, diamond-like carbons (DLC), fullerenes (C ₆₀ ), silicon nanowires, and combinations thereof. have.

On the other hand, the electron emission unit may be formed of a tip structure having a pointed tip mainly made of molybdenum (Mo) or silicon (Si).

In the drawing, the circular electron emitters 20 are arranged in a line along the longitudinal direction of the cathode electrode 14, but the shape of the electron emitter 20, the number and arrangement per pixel area, etc. are illustrated. It is not limited to the example and can be variously modified.

The focusing electrode 26, which is a third electrode, is formed on the gate electrodes 18 and the first insulating layer 16. A second insulating layer 28 is positioned below the focusing electrode 26 to insulate the gate electrodes 18 and the focusing electrode 26, and passes the electron beam through the focusing electrode 26 and the second insulating layer 28. Openings 261 and 281 are provided. The openings 261 and 281 may be formed in each electron emission unit 20 or one in each unit pixel, and the second case is illustrated in the drawing.

Next, on one surface of the second substrate 12 opposite to the first substrate 10, the fluorescent layer 30, for example, the red, green, and blue fluorescent layers 30R, 30G, and 30B may be randomly selected from each other. It is formed at intervals, and a black layer 32 is formed between the fluorescent layers 30 to improve the contrast of the screen. The fluorescent layer 30 is disposed so that the fluorescent layers 30R, 30G, and 30B of one color correspond to the unit pixels set on the first substrate 10.

An anode electrode 34 made of a metal film such as aluminum (Al) is formed on the fluorescent layer 30 and the black layer 32. The anode electrode 34 receives the high voltage necessary for accelerating the electron beam from the outside to maintain the fluorescent layer 30 in a high potential state, and visible light emitted toward the first substrate 10 of the visible light emitted from the fluorescent layer 30. Is reflected toward the second substrate 12 to increase the brightness of the screen.

The anode electrode may be formed of a transparent conductive film such as indium tin oxide (ITO). In this case, the anode electrode is positioned on one surface of the fluorescent layer 30 and the black layer 32 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.

Spacers 36 (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 the first substrate 10 and the second substrate 12. Keep the spacing constant). The spacers 36 are positioned corresponding to the black layer 32 so as not to invade the fluorescent layer 30.

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 electrode 26, and the anode electrode 34 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 26 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 34 is a voltage necessary 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 unit 20 in the unit pixels in which the voltage difference between the cathode electrode 14 and the gate electrode 18 is greater than or equal to a threshold, and electrons are emitted therefrom. The emitted electrons are focused through the opening 261 of the focusing electrode 26 to the center of the electron beam bundle, and are attracted to the fluorescent layer 30 of the corresponding unit pixel by being attracted by the high voltage applied to the anode electrode 34. It emits light.

In the above-described driving process, the electron emission display device of the present embodiment can reduce the voltage drop by reducing the line resistance of the cathode electrode 14 through the auxiliary electrode 24, thereby increasing electron emission uniformity and emission uniformity of the unit pixels. .

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

Referring to the drawings, the electron emission display device of the present embodiment provides a structure in which the auxiliary electrodes are further formed on the gate electrodes 38 and the focusing electrode 40 based on the configuration of the first embodiment described above.

That is, in the present embodiment, the gate electrode 38 is formed on the main electrode 42 and the main electrode 42, and the auxiliary electrode in which the molybdenum layer 441 and the aluminum layer 442 are sequentially stacked from the main electrode 42. It consists of 44. The focusing electrode 40 also includes the main electrode 46 and the auxiliary electrode 48 formed on the main electrode 46 and in which the molybdenum layer 481 and the aluminum layer 482 are sequentially stacked from the main electrode 46. .

The main electrodes 42 and 46 of the gate electrode 38 and the focusing electrode 40 may be chromium layers, and are not etched in the etchant of the auxiliary electrodes 44 and 48. The gate electrode 38 and the focusing electrode 40 may reduce the line resistance by driving the line resistance by the auxiliary electrodes 42 and 46.

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

Referring to the drawings, in the present embodiment, the cathode electrode 50 includes a main electrode 52 made of a transparent conductive film such as ITO, and an auxiliary electrode 54 formed on the main electrode 52. Reference numeral 54 is a structure in which the first molybdenum layer 541, the aluminum layer 542, and the second molybdenum layer 543 are sequentially stacked from the main electrode 52. The second molybdenum layer 543 serves to protect the aluminum layer 542 to prevent damage or diffusion of the aluminum layer 542 that may occur in a subsequent process.

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

Referring to the drawings, the electron emission display device of the present embodiment provides a structure in which the auxiliary electrodes are further formed on the gate electrodes 56 and the focusing electrode 58 based on the configuration of the above-described third embodiment.

In other words, in the present embodiment, the gate electrode 56 is formed on the main electrode 60, the main electrode 60, and sequentially from the main electrode 60 to the first molybdenum layer 621, the aluminum layer 622, and the second electrode. The auxiliary electrode 62 in which the molybdenum layer 623 is stacked is formed. The focusing electrode 58 is also formed on the main electrode 64, on the main electrode 64, and sequentially from the main electrode 64, the first molybdenum layer 661, the aluminum layer 662, and the second molybdenum layer 663. The laminated auxiliary electrode 66 is formed.

The main electrodes 60 and 64 of the gate electrode 56 and the focusing electrode 58 may be chromium layers, and are not etched in the etchant of the auxiliary electrodes 62 and 66. The gate electrode 56 and the focusing electrode 58 may reduce the line resistance by the auxiliary electrodes 62 and 66 described above to suppress the voltage drop during driving.

In the above, the field emission array (FEA) type electron emission display device which emits electrons from the electron emission portion by using an electric field has been described. However, the present invention is not limited to this FEA type, but can be easily applied to other types of electron emission display devices. Applicable

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 such, the electron emission display device according to the present invention improves display quality by reducing the line resistance of the driving electrodes to increase the electron emission amount per unit pixel and the emission uniformity of the fluorescent layer. In addition, the electron emission display device according to the present invention can simultaneously pattern the entire auxiliary electrode into one etchant to simplify the manufacturing process, suppress chemical reaction between the driving electrodes and the auxiliary electrode, and pattern the auxiliary electrode by etching. When the driving electrodes are etched together can be suppressed.

Claims (9)

A substrate; Cathode electrodes formed on the substrate; Gate electrodes positioned to be insulated from the cathode electrodes; And And electron emission parts electrically connected to the cathode electrode, Each of the cathode electrodes, A main electrode made of a transparent conductive film; And an auxiliary electrode disposed on one surface of the main electrode and formed of a molybdenum layer and an aluminum layer stacked from the main electrode. The method of claim 1, And the auxiliary electrode further comprises an additional molybdenum layer stacked over the aluminum layer. The method of claim 1, And an auxiliary electrode on which the gate electrode is located on one surface of the main electrode, and a molybdenum layer and an aluminum layer are laminated from the main electrode. The method of claim 3, And the auxiliary electrode further comprises an additional molybdenum layer laminated on the aluminum layer. The method of claim 1, And a focusing electrode positioned over the cathode and gate electrodes and insulated from the cathode and gate electrodes. The method of claim 5, And the auxiliary electrode comprising a main electrode and an auxiliary electrode formed on a surface of the main electrode and having a molybdenum layer and an aluminum layer laminated from the main electrode. The method of claim 6, And the auxiliary electrode further comprises an additional molybdenum layer laminated on the aluminum layer. 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 phase carbons, fullerenes (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; Fluorescent layers formed on one surface of the other substrate; And An anode formed on one surface of the fluorescent layers Electron emission display device comprising a.

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