KR20020007495A - electron gun applying cold cathode - Google Patents

Abstract

PURPOSE: An electron gun having a cold cathode is provided to reduce a divergent angle of electron by forming a grid having apertures of various shapes and electron emission sources of uniform height. CONSTITUTION: A substrate(61) is formed with a glass or a wafer. A conductive cathode(62) is formed on an upper face of on the substrate(61). An insulating layer(63) is formed on an upper face of the conductive cathode(62). An electron emission source(64) is formed on an upper face of the cathode(62) through a cavity(65). The cavity(65) is formed on a part of the insulating layer(63). The electron emission source(64) has an erect shape. The electron emission source(64) is formed with a carbon nano tube or a graphite or a diamond like carbon. A grid(66) of metal material is formed on an upper face of the insulating layer(63). A multitude of apertures(66a) are formed in the grid(66) to emit electron beam from the electron emission sources(64). The apertures(66a) have various shapes.

Description

Electron gun applying cold cathode

The present invention relates to an electron gun, and more particularly, to an electron gun employing a gate electrode and a cold cathode having an improved structure of an electron emission source for emitting electrons.

Typically, the electron gun used in the cathode ray tube was used as a cathode structure of the heated cathode type (heated cathode type) that requires a separate heater. The electron gun emits hot electrons from the cathode structure as a predetermined potential is applied to the cathode structure and each electrode, and an electron lens is formed between the electrodes. Accordingly, the electron beam is focused and accelerated while passing through the electron lens formed between each electrode. However, the electron gun employing the hot cathode type has a long time from the time when the voltage is applied to the heater to the time at which the electrons are emitted from the electron emitter, so that the time for image formation is long, and the overall power consumption due to the driving power of the heater Big power In addition, the electron emission characteristics of the three electron emission sources for red, green, and blue have large differences from each other.

Recently, in order to eliminate structural disadvantages of the hot cathode electron gun, a cold cathode electron gun having no heater has been developed. The electron gun uses a cathode structure for a field emission display. Unlike the cathode structure, which heats an electron emitting material to generate hot electrons, the electron gun forms a strong electric field in the metallic electron emitting tip to form a quantum mechanical transmission phenomenon. Is used to emit electrons from an electron emission source.

Korean Patent Publication No. 96-32537 discloses an example of such an electron gun.

Referring to FIG. 1, an electron gun includes a conductive substrate 11, a conical electron emission source 12 disposed on the substrate 11, and at least one cavity 13 in which the electron emission source 12 is disposed. ) And a cold cathode 10 made of an insulator layer 15 interposed between the substrate 11 and the gate electrode 14. At this time, the region A of the gate electrode 14 around the end of the electron emission source 12 and the region B of the gate electrode 14 other than the region A have different potential drop characteristics. .

The cold cathode 10 forms an insulator layer 15 and a gate electrode 14 on the substrate 11, and then forms an electron emission source 12. This manufacturing process has a problem in that the functional layers have a thin film form, and a process of forming a plurality of cavities 13 and forming a film is complicated. In addition, since the divergence angle of electrons emitted from the electron emission source 12 in the form of a micro tip is large, there is a disadvantage in that the focus characteristic is deteriorated.

2 shows an example of the electron gun 20 disclosed in US Pat.

Referring to the drawings, the electron gun 20 has a plurality of electron emission sources 22, 23, 24 are disposed on the substrate 21 with respect to the central axis 200, the insulating film 25, and The gate electrode 26 is formed on the insulating film 25. The focus electrode 27 is provided around the electron emission sources 22, 23, 24. First and second auxiliary electrodes 28 and 29 are disposed on the electron emission sources 22, 23, and 24.

When a voltage of 6 kV is applied to the first auxiliary electrode 28 and a voltage of 25 kV is applied to the second auxiliary electrode 29, the electron lens is applied to the first and second auxiliary electrodes 28 and 29. Is formed. The electrons emitted from the electron emission sources 22, 23 and 24 pass through the electron lens unit in a predetermined trajectory.

However, in order to reduce the cause of deterioration of focus characteristics, the electron gun 20 has to install separate focusing first and second auxiliary lenses 28 and 29 on the front surface of the triode including the electron emission source. Even if a plurality of auxiliary lenses 28 and 29 are provided, there is uncertainty as to whether the focus characteristic is improved.

3 illustrates an electron gun 30 disclosed in Korean Patent Laid-Open No. 97-23527.

Referring to the drawings, the electron gun 30 includes the substrate 31, the plurality of electron emission sources 32 formed on the substrate 31, the electron emission source 32 and the surroundings thereof except for the substrate. A pair of insulator layers (not shown) formed on the insulator layer (31), a gate electrode (33) formed on the insulator layer and having an opening surrounding the electron emission source (32), and surrounded by the gate electrode (33). The focusing electrodes 34a are divided into at least four parts so that the focusing electrodes 34a, 34b, 35a, and 35b of the plurality of electrodes are faced with the gate electrode 33 therebetween so as to be controlled at the same time. ) 34b, 35a, 35b.

By the way, the electron gun 30 is provided with a plurality of horizontal and vertical focusing electrodes 34a, 34b, 35a, 35b corresponding to the periphery where the electron emission source 32 and the gate electrode 33 are formed. This structure is known to have a greater effect in preventing the electron beam from being distorted around the screen than improving the focus characteristic of the emitted electrons.

4 illustrates a state in which an electric field is distributed in the conventional cold cathode 40.

Referring to the drawings, the cold cathode 40 is a state in which a voltage of 150V is applied between the cathode and the gate electrode 42 formed on the insulator layer 41, and a voltage of 1KV is applied to the anode. In the micro-tip electron emission source 43, the electric field is concentrated at a sharp point on the top of the tip, and the divergence angle of electrons is large, and the influence of the gate electrode 42 in the form of a thin film having a thickness of about 1.0 micrometer is little. . Therefore, as the divergence angle of the electron beam increases, the focus characteristic of the cathode ray tube deteriorates.

The present invention was devised to solve the above problems, and employs a cold cathode having a grid having various types of apertures on an insulator and an electron emission source having a uniform height to reduce the divergence angle of electrons. The purpose is to provide an electron gun.

1 is a cross-sectional view showing a portion of a cold cathode according to a first embodiment of the present invention;

2 is a cross-sectional view showing a part of an electron gun according to a second conventional embodiment;

3 is a plan view showing a part of an electron gun according to a third conventional embodiment,

4 is a schematic diagram showing a state in which an electric field is distributed in a conventional cold cathode;

5 is an exploded perspective view showing an electron gun according to the present invention;

6 is a cross-sectional view showing the cold cathode of FIG.

FIG. 7A is a sectional view showing a first embodiment of the gate electrode of FIG. 5; FIG.

7B is a cross-sectional view illustrating a second embodiment of the gate electrode of FIG. 5;

7C is a cross-sectional view showing a third embodiment of the gate electrode of FIG. 5;

8 is a sectional view showing an electron emission source portion of FIG. 5;

9 is a cross-sectional view illustrating a state in which FIG. 7A and FIG. 8 are combined;

10 is a schematic diagram showing a state in which an electric field is distributed in the cold cathode according to the present invention.

<Brief description of symbols for the main parts of the drawings>

10,20,30,40,50,100 ... electron gun

11,21,31 ... substrate 12,22 ... emission source

13 ... cavity 14,26,33,42 ... gate electrode

15,25,41 Insulation layer 32,43 ...

71,73,75 ... grid 61 ... substrate

62 Cathode 63,110 Insulator layer

64,130 ... Emission source 65 ... cavity

66,120 gate electrode

In order to achieve the above object, the electron gun employing the cold cathode of the present invention,

Board;

A cathode formed on the substrate;

An insulator layer formed on an upper surface of the cathode and having a plurality of cavities;

Red, green, and blue electron emission sources formed on the upper surface of the cathode corresponding to the cavity; And

And a gate electrode formed on an upper surface of the insulator layer and formed of a grid in which a plurality of opening holes are formed on the electron emission source.

In addition, the electron emission source is characterized in that it is formed in an upright shape with a uniform height on the upper surface of the cathode so that the red, green, blue electron beam can be emitted.

In addition, the electron emission source is a carbon material, characterized in that any one selected from carbon nanotubes, graphite, DL.

Further, the gate electrode is a thick metal material, characterized in that the thickness of 5 to 30 micrometers.

In addition, the gate electrode is characterized in that the cross section is any one selected from trapezoidal, inverted trapezoidal, hexagonal.

Hereinafter, an electron gun of a cold cathode type according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

5 illustrates an electron gun 50 according to an embodiment of the present invention.

Referring to the drawings, the electron gun 50 is provided with a cathode structure 52 having a cold cathode 51 having an electron emission source as a field emission device. In front of the cathode structure 52, a focus electrode 53 and a final acceleration electrode 54 for focusing and accelerating the electron beam emitted from the cold cathode 51 are provided.

Here, a plurality of cold cathodes 51 are provided for each of red, green, and blue, and red, green, and blue electron beam passing holes 53a and 53b formed on one surface of the focus and final acceleration electrodes 53 and 54. 54a is installed correspondingly.

The structure of the cold cathode is shown in detail in FIG.

Referring to the drawings, the cold cathode 60 is provided with a substrate 61 made of glass or a wafer. On the upper surface of the substrate 61, a conductive cathode 62 such as silver paste is formed. An insulator layer 63 made of silicon oxide (SiO ₂ ) is formed on the upper surface of the cathode 62.

At this time, the electron emission source 64 is formed on the upper surface of the cathode 62. That is, part of the insulator layer 63 does not cover the cathode 62, and the part is open. Through the cavity 65, an electron emission source 64 capable of emitting an electron beam is formed on the upper surface of the cathode 62 for red, green, and blue.

Unlike the prior art, the electron emission source 64 is not formed in a conical micro tip made of metal such as molybdenum, but is formed in an upright shape with a uniform height on a part of the surface of the cathode 62.

As the electron emission source 64, it is preferable to use a carbon material having excellent conductivity and having a large amount of electron emission. For example, a carbon nano tube, graphite, or diamond like materials such as carbon and DLC are suitable.

On the other hand, the upper surface of the insulator layer 63 is provided with a grid 66 of metal material used as the gate electrode. The grid 66 is formed with a plurality of opening holes 66a to emit an electron beam from the electron emission source 64. The grid 66 may form various shapes of the opening hole 66a. A factor influencing this is the divergence angle of the electron beam.

7A-7C illustrate various embodiments of such a grid.

Referring to FIG. 7A, a plurality of opening holes 72 are formed in the grid 71 to allow electron beams emitted from an electron emission source to pass therethrough. The formation of the opening 72 is related to controlling the angle at which the electron beam is emitted as described above. Looking at the grid 71 by cutting the cross section, the grid 71 is trapezoidal in shape.

In the case of FIG. 7B, the cross-sectional shape of the grid 73 in which the opening hole 74 is formed has a hexagonal shape. In this case, the electron emission angle is smaller than that in FIG. 7A.

In the case of FIG. 7C, a grid 75 having a shape opposite to that of FIG. 7A is illustrated.

That is, the cross section of the grid 75 maintains an inverted trapezoidal shape, and a plurality of opening holes 76 having a shape corresponding thereto are formed in the grid 75. In this case, as in the case of FIG. 7B, the electron emission angle is smaller than that illustrated in FIG. 7A.

The grid illustrated in Figs. 7A to 7C is a thick film metal material, and the thickness thereof is about 5 to 30 micrometers so as to reduce the divergence angle of the electron beam emitted from the electron emission source when voltage is applied and to form an aperture hole. It can be said to be advantageous. In this case, it is preferable to use an alloy containing SUS, copper, iron, or nickel as a main component as a grid.

The grid having the above shape can be manufactured to have a desired aperture by arranging a mask having a pattern corresponding to the aperture in a metal material, applying an appropriate amount of photoresist, and performing etching after exposure and development. .

A functional layer such as an electron emission source is formed on a substrate separately from the completed grid as described above.

That is, as shown in FIG. 8, the cathode 82 having conductivity such as silver paste is formed on the wafer 81 made of wafer or transparent glass. The insulator layer 83 made of silicon oxide or the like is applied to the upper surface of the cathode 82 except for the portion where the electron emission source 84 is to be formed. On the other hand, the cathode 82 is formed by dividing the electron emission source 84 for emitting electrons into three, red, green, blue.

The substrates 81 formed with the completed grids and the electron emission sources 84 are coupled to each other as shown in FIG. 9 to use the grids 85 as gate electrodes.

10 shows a state in which an electric field is distributed in the cold cathode 100 according to the present invention.

Referring to the drawings, the cold cathode 100 is a state in which a voltage of 150V is applied between the cathode and the gate electrode 120 attached to the upper surface of the insulator layer 110, a voltage of 1kV is applied to the anode. In this case, since the concentration of the electric field does not occur, the angle of divergence of the electron beam emitted from the electron emission source 130 is relatively low, and the electrons emitted as the electric field is bent by the gate electrode 120 converge. It will work in the form of.

As described above, the electron gun employing the cold cathode of the present invention has a gate electrode made of a grid made of metal, and an electron emission source of an upright form having a uniform height is formed on the upper surface of the cathode. The divergence angle of the emitted electrons can be reduced to improve the focus characteristic. In addition, the manufacturing process is easy by adopting a method of separately manufacturing the grid and other portions and combining them with each other.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (8)

Board; A cathode formed on the substrate; An insulator layer formed on an upper surface of the cathode and having a plurality of cavities; Red, green, and blue electron emission sources formed on the upper surface of the cathode corresponding to the cavity; And And a gate electrode formed on a top surface of the insulator layer, the gate electrode being a grid having a plurality of opening holes formed on the electron emission source. The method of claim 1, The electron emission source is an electron gun employing a cold cathode, characterized in that formed in an upright shape with a uniform height on the upper surface of the cathode so that red, green, blue electron beam can be emitted. The method of claim 2, The electron emission source is an electron gun employing a cold cathode, characterized in that the carbon material. The method of claim 3, The electron emission source is an electron gun employing a cold cathode, characterized in that any one selected from carbon nanotubes, graphite, DL. The method of claim 1, And said gate electrode is a thick metal film. The method of claim 5, And said gate electrode has a thickness of 5 to 30 micrometers. The method of claim 5, And said gate electrode is any one selected from a trapezoid, an inverted trapezoid, and a hexagon. The method of claim 1, And the gate electrode, the cathode, the substrate on which the electron emission source and the insulator layer are formed, are each manufactured separately and combined with each other.