JPH0636681A - Cold cathode electron gun - Google Patents

Abstract

PURPOSE:To provide an electron gun which is stable, of high reliability, and has a low power consumption rate and high current density for an electron beam. CONSTITUTION:A cold cathode 1 uses a cold cathode chip 5 derived from vacuum microelectronics technique and has a structure in which the end of an emitter 10 from which electrons are emitted is projected beyond the gate electrode 9 of the cold cathode chip 5. A G1 electrode 2 for applying either a positive or negative voltage to the emitter 10 of the cold cathode chip 5 and a G2 electrode 3 for applying a positive voltage to the emitter 10 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold cathode electron gun, and more particularly to a cold cathode electron gun using a cold cathode to which a vacuum microelectronic technique is applied.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of an example of a conventional electron gun for a CRT (cathode ray tube) using a hot cathode.

As shown in FIG. 3, the hot cathode 31 is heated by a heater (not shown). A negative voltage is applied to the hot cathode 31 of the first electrode (hereinafter, referred to as G1 electrode) 2. The second electrode (hereinafter, referred to as G2 electrode) 3 is applied with a positive voltage of several 100 V with respect to the hot cathode 31. A positive voltage of several kV is applied to the hot cathode 31 at the third electrode (hereinafter, referred to as G3 electrode) 4.
An electron emitting material 35 is applied to the surface of the hot cathode 31, and when the hot cathode 31 is heated to a high temperature, the electron emitting material 35 is applied.
Electrons are emitted from the electron beam, and an electron beam 6 is formed according to the electric field distribution created by the G1 electrode 2, the G2 electrode 3, and the G3 electrode 4.

FIG. 4 is a sectional view of an example of a conventional CRT electron gun using a cold cathode.

As shown in FIG. 4, the cold cathode 1 is placed at the position of the hot cathode 31 of the electron gun shown in FIG. 3, and the other electrodes, that is, the G1 electrode 2, the G2 electrode 3, and the G3 electrode 4 are the same as those in FIG. It is placed in a position and almost the same voltage is applied. On the surface of the cold cathode 1, a cold cathode chip 5 is attached instead of the electron emission material 35 shown in FIG.

FIG. 5 is a partially enlarged sectional view of the cold cathode chip of FIG.

As shown in FIG. 5, a conventional cold cathode chip 5 is used.
Is composed of a substrate 7, an insulating film 8, a gate electrode 9 and an emitter 10. The tip of the emitter 10 is made extremely sharp, and the gate electrode 9 is arranged in the immediate vicinity thereof so as to surround it. Therefore, the emitter 10
On the other hand, when a voltage of several tens of volts or more is applied to the gate electrode 9, an extremely high electric field is applied to the tip of the emitter 10,
Electrons are emitted from the entire surface of the cold cathode chip 5. A part of the emitted electrons, that is, the electrons emitted from the central portion of the cold cathode chip 5 forms an electron beam 6 according to the electric field distribution created by the G1 electrode 2, the G2 electrode 3, and the G3 electrode 4. On the other hand, the electrons emitted from the peripheral portion of the cold cathode chip 5 are reflected by the G1 electrode 2 to which a negative voltage is applied and reach the gate electrode 9.

[0008]

In the conventional hot cathode electron gun shown in FIG. 3, the hot cathode 31 is set to 700 to 1000.
In order to keep the temperature at 0 ° C, a heater power supply and electric power of 1 to 4 W are required. Further, structures such as electrodes around the hot cathode 31 are also heated by the hot cathode 31, and the temperature rises. As a result, the dimensions of each structure change between when the hot cathode 31 is heated and when it is not heated.
It is necessary to design considering the dimensional change due to temperature change. Further, there is a problem that a part of the cathode material is evaporated by the temperature and the cathode emission current is decreased with time, and this phenomenon determines the life of the cathode.

In the conventional cold cathode electron gun shown in FIGS. 4 and 5, since electrons are extracted by the positive voltage applied to the gate 9 of the cold cathode chip 5 over the entire surface of the cold cathode 1, the emitter in the peripheral portion is The electrons emitted from 10 are reflected by the G1 electrode 2 to which a negative voltage is applied and reach the gate electrode 9. As a result, the gate electrode 9 is heated, and the gate electrode 9 is deformed, discharge due to gas release occurs, and the cold cathode 1 is deteriorated or destroyed.

An object of the present invention is to provide a cold cathode electron gun which has no deterioration or destruction and has a long life.

[0011]

According to the present invention, there is provided one of a conductive substrate and a semi-conductive substrate, an insulating layer laminated on the substrate, and a metal layer laminated on the insulating layer. And a micro-cooling formed by the metal layer and an electron-emitting electrode of one of conductive and semi-conductive with a sharp tip formed in a hole provided in a part of the insulating layer. A cold cathode chip in which a large number of cathodes are lined up, a first electrode having a hole in a central portion arranged in a position close to the cold cathode chip, and a central portion arranged in a position close to the first electrode In a cold cathode electron gun having a second electrode with a hole formed in the hole, the tip of the electron emission electrode is made to protrude beyond the surface of the metal layer.

[0012]

Function: Electrons are emitted only from the tip of the emitter in the portion where an equipotential surface that is positive with respect to the emitter and has a certain potential or more is formed near the surface of the cold cathode, and all the emitted electrons are components of the electron beam. Therefore, it does not return to the cold cathode, especially the gate electrode. Therefore, it is possible to prevent the deterioration or destruction of the cold cathode due to the deformation of the gate electrode due to the heating of the gate electrode or the discharge due to the gas release.

In addition to this, since the cold cathode does not need to be heated, a power source and electric power for heating are not required, and since it is not necessary to keep the cathode at a high temperature, thermal design is easy and a special material is used. Because there is no need to vaporize the material,
It is possible to realize an electron gun in which the emission current is less likely to deteriorate over time.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

1A and 1B are a sectional view of a first embodiment of the present invention and a partially enlarged sectional view of a cold cathode chip thereof. In the figure, 1 is a cold cathode, 2 is a G1 electrode, 3 is G2
An electrode, 4 is a G3 electrode, 5 is a cold cathode chip, 6 is an electron beam, 7 is a substrate, 8 is an insulating layer, 9 is a gate electrode, and 10 is an emitter.

In the first embodiment, as shown in FIGS. 1A and 1B, the cold cathode chip 5 is characterized in that the tip of the emitter 10 protrudes beyond the gate electrode 9. In the conventional structure in which the tip of the emitter 10 is on substantially the same surface as the gate electrode 9, the amount of current emitted from the emitter 10 is determined by the voltage between the gate electrode 9 and the emitter 10, whereas the emission from the emitter 10 is determined. The amount of electric current is determined by the potentials of the gate electrode 9, the G1 electrode 2 and the G2 electrode 3 [International Electron Device Meeting (International Electron Electron Meeting).
n Device Meeting) 1991 Technical Digest, 213-215].

In order to operate this electron gun, for example, the cold cathode 1, the substrate 7 and the emitter 10 are set to the same potential, and the G1 electrode 2 has a DC of -40V, the G2 electrode 3 has a DC of 500V, and a G3 electrode with the same potential as a reference. DC of 7 kV is applied to the gate electrode 9, and DC positive or negative voltage is applied to the gate electrode 9. In order to control the amount of current of the electron beam 6, a control voltage is superposed on the G1 electrode 2 or the gate electrode 9.

Next, the operation when a control voltage is applied to the G1 electrode 2 will be described. Since the space between the cold cathode 1 and the G1 electrode 2 and the space between the G1 electrode 2 and the G2 electrode 3 are made extremely narrow,
The voltage applied to the G2 electrode 3 creates a positive electric field near the surface of the cold cathode chip 5 through the hole of the G1 electrode 2. G1 electrode 2
Is −40V, the electric field at the tip of the emitter 10 is 1 × 10
It is assumed to be about ⁷ V / cm. At this time, the electric field at the tip of the emitter 10 is just below the threshold for emitting current. When the potential of the G1 electrode 2 is set to −30 V, the tip of the emitter 10 at the center of the cold cathode chip 5 exceeds about 4 × 10 ⁷ V / cm, and current is emitted from this part. At the periphery, the electric field at the tip of the emitter 10 is below this threshold, so no current is emitted. When the potential of the G1 electrode 2 is further increased, the portion where the electric field at the tip of the emitter 10 exceeds the threshold is further widened, and at the same time, the electric field at the tip of the emitter 10 at the center is further strengthened and more current is emitted. However, the peripheral portion of the cold cathode chip 5 that directly faces the G1 electrode 2 is strongly influenced by the potential of the G1 electrode 2 to which a negative voltage is applied and is not influenced by the potential of the G2 electrode 3, so that electrons are not emitted. Absent.

As described above, in the present embodiment, electrons are emitted only from the portions corresponding to the holes formed in the G1 electrode 2 and the G2 electrode 3, and no electrons are emitted from the peripheral portion. Therefore, in the present embodiment, only the effect shown in the above-mentioned reference that the electron emission is affected by the potentials of the gate electrode 9 and the collector electrode (corresponding to the composite of the G1 electrode 2 and the G2 electrode 3 of the present embodiment). However, the electrons are emitted only from the central portions of the holes of the G1 electrode 2 and the G2 electrode 3, and the emission of electrons from the peripheral portion can be suppressed, and the electrons emitted from the cold cathode 1 can be emitted from the G1 electrode 2 and the gate electrode. The effect that there is no possibility of reaching 9 is obtained.

Even if the potential of the G1 electrode 2 is positive,
By properly setting the potential of the gate electrode 9, G
It is possible to keep the electric field at the tip of the emitter 10 below a threshold value in the peripheral portion of the cold cathode chip 5 that directly faces the first electrode 2 so that electrons are not emitted.

FIG. 2 is a partially enlarged sectional view of the vicinity of the cold cathode according to the second embodiment of the present invention.

In the second embodiment, as shown in FIG. 2, the emitter 10 that emits electrons is a G1 electrode 2 and a G2 electrode 3.
By arranging a structure in which the emitter 10 and the gate electrode 9 do not exist in the peripheral portion at almost the same position as that of the hole formed in the same area, the G
The amount of emission current and the region of the cold cathode 1 that emits the current are determined by the voltage of the first electrode 2, and the electrons emitted from the emitter 10 in the peripheral portion do not become an electron beam but the gate electrode 9
As in the first embodiment, there is no electron returning to the. Furthermore, in this embodiment, since there is no emitter 10 that emits electrons in the portion directly facing the G2 electrode, an excessive current flows through the G1 electrode 2 and the gate electrode 9 even if an abnormal voltage is applied to each electrode. There is no fear.

Further, since the electrostatic capacitance between the gate electrode 9 and the emitter 10 becomes the minimum necessary, the load of the drive circuit can be lightened even when the control signal is applied between the gate electrode 9 and the emitter 10.

In the first and second embodiments, the operation method of applying the control signal to the G1 electrode 2 has been described, but the same effect can be obtained when the control signal is applied to the emitter 10 or the gate electrode 9. Can be expected.

[0025]

As described above, according to the present invention, it is not necessary to heat the cathode, there is no need for a heating power source and electric power, and there is no need to keep the cathode at a high temperature. Since there is no need to use the electron gun, the electron beam has a high current density, and the material does not evaporate, there is an effect that it is possible to realize an electron gun with little possibility of deterioration of emission current with time.

Further, since the current does not flow into the gate electrode, there is an effect that it is possible to prevent the deterioration or destruction of the cathode due to the deformation of the gate electrode or the discharge due to the gas release.

Further, when the electron beam current amount is changed by controlling the G2 electrode, the current emission area of the cold cathode chip 5 increases when a large amount of current is required, so that the increase in current per emitter is suppressed, There is an effect that more stable operation can be expected.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention and a partially enlarged sectional view of a cold cathode chip thereof.

FIG. 2 is a partially enlarged cross-sectional view near a cold cathode according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of an example of a conventional CRT electron gun using a hot cathode.

FIG. 4 is a sectional view of an example of a conventional CRT electron gun using a cold cathode.

5 is a partially enlarged cross-sectional view of the cold cathode chip of FIG.

[Explanation of symbols]

 1 Cold Cathode 2 G1 Electrode 3 G2 Electrode 4 G3 Electrode 5 Cold Cathode Chip 6 Electron Beam 7 Substrate 8 Insulating Layer 9 Gate Electrode 10 Emitter 31 Hot Cathode 35 Electron Emitting Material

Claims (2)

[Claims] 1. An electrically conductive or semi-conductive substrate, an insulating layer laminated on the substrate, a metal layer laminated on the insulating layer, the metal layer and the insulation. Cold cathode chip formed by arranging a large number of micro cold cathodes, each of which is formed in a hole provided in a part of a layer and has an electron emission electrode of either one of conductive and semi-conductive with a sharpened tip When,
A first electrode having a hole in a central portion arranged in a position close to the cold cathode chip, and a second electrode having a hole in a central portion arranged in a position close to the first electrode The cold cathode electron gun according to claim 1, wherein the tip of the electron emission electrode is projected from the surface of the metal layer. 2. The cold cathode electron gun according to claim 1,
A cold cathode electron gun characterized in that the distribution of electron emitting electrodes is made to substantially coincide with the position and size of the hole in the center of the first electrode.