JPH09306374A - Preventive method of floating electron emission from first control electrode of cathode-ray tube and first control electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent emission of a floating electron, reduce floating capacity between electrodes, and improve an image quality by covering a part where a first control electrode is opposed to a cathode substance covering surface with a substance such as gold which has a high work function and is low in reactivity with a cathode substance. SOLUTION: A part where a plate-like first control electrode G1 of a cathode-ray tube is opposed to a cathode substance covering surface (a) of a cathode K, is covered with a substance such as Au, Ni and Co which has a high work function and is low in reactivity with a cathode substance (a) by a method such as ion sputtering, evaporation and plating. Therefore, even if barium (b) sticks to a surface where the first control electrode G1 is opposed to the cathode and exists as a barium oxide by oxidizing gas in the cathode-ray tube, reaction with a reducing agent contained in a raw material of the G1 is restrained by an inactive metallic coating film, and generation of a floating electron is restrained, and an image quality in a dark image screen can be improved. An evil influence by discharge of the floating electron generated by the G1 at operating time of the cathode-ray tube can also be restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a first control electrode of a cathode ray tube, and more particularly, to forming an inert metal coating on the cathode facing surface of the first control electrode to cut an electron beam. The present invention relates to a method for preventing floating electron emission from a first control electrode of a cathode ray tube and a first control electrode, which have improved image quality in a dark screen when turned off.

[0002]

2. Description of the Related Art Conventionally, as a first control electrode (hereinafter, abbreviated as a G1 electrode as appropriate) which constitutes an electron gun of a cathode ray tube, a non-magnetic metal such as SUS402 is processed into a plate shape or A cup-shaped electrode is used. The G1 electrode is arranged in the vicinity of the cathode and functions to control the electric field intensity of the cathode coated with the electron emissive material to turn on / off the electron beam. By the way, in recent years, a cathode ray tube is used for a display of a computer, and thus a high resolution is required. And in order to meet such a request, G
It is necessary to reduce the hole diameter of one electrode and also reduce the distance between the cathode and the G1 electrode. However, G
If the hole diameter of one electrode is reduced or the distance between the cathode and the G1 electrode is reduced, floating electrons are generated, which adversely affects the image quality. This state will be described with reference to the drawing.

FIG. 2 is a schematic diagram for explaining the generation state of floating electrons in the cathode and the G1 electrode in the cathode ray tube. In the figure, G1 is a G1 electrode, K is a cathode, a is a cathode material, b is barium, c is a floating electron, and dKG is a distance between the cathode K surface and the G1 electrode.

As shown in FIG. 2, the G1 electrode G1 is
The cathode material a is applied so as to face the cathode K. Then, as described above, the G1 electrode G1
The hole diameter of G1 electrode G1
When the distance dKG from and is reduced, the cathode ray tube (CRT)
During the activation process and operation of the cathode K during the manufacture of, barium b, which constitutes the cathode substance a, is released into the tube,
The G1 electrode G1 is attached to the surface facing the cathode K. The barium (Ba) b is combined with an oxidizing gas such as carbon dioxide (CO ₂ ) existing in the cathode ray tube,
Barium oxide (BaO) is produced.

This barium oxide (BaO) is contained in the material metal of the G1 electrode G1 such as manganese (M).
With a small amount of reducing agent as in n), electrons are easily released, which causes floating electrons c.
The stray electrons c thus generated are generated even when the regular electrons emitted from the cathode substance a applied to the cathode K surface are suppressed, that is, in the so-called cut-off state. The presence of c causes a significant deterioration in image quality.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a high-quality image display in a conventional cathode ray tube by suppressing generation of stray electrons c which causes deterioration of image quality. And Specifically, in a cathode ray tube that requires high resolution, it is necessary to reduce the hole diameter of the G1 electrode G1 and the distance dKG between the cathode K surface and the G1 electrode G1. It is another object of the present invention to improve the image quality deterioration in a dark screen in which the electron beam is cut off due to the influence of the increase in stray capacitance between the electrodes. Furthermore, the G1 electrode which solved such a subject is provided.

[0007]

According to the method for preventing floating electron emission of claim 1, the portion of the first control electrode (G1) facing the cathode material coating surface has a high work function and is highly reactive with the cathode material. A material such as low Au (gold) is coated by a method such as ion sputtering, vapor deposition, and plating.

In the method for preventing floating electron emission according to claim 2, a material having a high work function and a low reactivity with the cathode material in the method for preventing floating electron emission according to claim 1 is Ni (nickel), Co (cobalt), Cd (Cadmium), Sb
(Antimony), Cu (copper), Pb (lead), Bi (bismuth), Tl (thallium), Ag (silver), Pd (palladium), Pt (platinum), Ru (ruthenium), Rh
(Rhodium), Os (osmium), Ir (iridium), etc. are used.

In the method for preventing floating electron emission according to claim 3, the thickness for coating a material having a high work function and a low reactivity with the cathode material in the method for preventing floating electron emission according to claim 1 is set to at least 10 μm. ing.

In the first control electrode of claim 4, Au (gold), Ni (nickel), C having a high work function and a low reactivity with the cathode material is provided in a portion facing the cathode material coating surface.
o (cobalt), Cd (cadmium), Sb (antimony), Cu (copper), Pb (lead), Bi (bismuth), T
l (Thallium), Ag (Silver), Pd (Palladium), P
Substances such as t (platinum), Ru (ruthenium), Rh (rhodium), Os (osmium) and Ir (iridium) are coated by ion sputtering, vapor deposition, plating or the like.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a method for preventing floating electron emission from a first control electrode of a cathode ray tube and a first control electrode of the present invention will be described with reference to the drawings. This embodiment corresponds to the inventions of claims 1 to 4. In the present invention, as described in the related art with reference to FIG. 2, the cause of the floating electrons c is manganese contained in the material metal of the first control electrode (G1) to which the cathode material is attached. Focusing on the fact that a small amount of reducing agent such as (Mn) is present, many experiments were repeated, and as a result, it was found that a portion of the first control electrode (G1) facing the cathode material coated surface was The feature is that the generation of the stray electrons c is suppressed by forming a film of a substance having a high work function and a low reactivity with the cathode substance.

FIG. 1 is a view for explaining a method for preventing floating electron emission from the first control electrode of the cathode ray tube according to the present invention, and is a process chart showing a process at the time of assembling the electron gun. In the figure, 1 is a holder, 2 is a metal coating, 3a and 3b are spacers, 4 is a sleeve, 5 is a cathode holder, and G1 is G1.
Electrodes, G2 is a G2 electrode, and S1 to S8 are processes.

In FIG. 1, steps S1 to S8 are shown in the center, a side view of an electron gun assembled in each step is shown on the left side, and parts used in each step are shown on the right side. In FIG. 1, in step S1, for a plate-shaped G1 electrode G1 made of, for example, an iron-nickel alloy or an iron-cobalt alloy, gold (Au) having a thickness of at least 10 μm is vapor-deposited on at least one surface on the cathode side, The metal coating 2 is formed (G1 electrode coating treatment). The next steps S2 and S3 are brazing steps. First, in step S2, one of the holders 1 made of an insulating material (preliminarily metallized) is
The two spacers 3a and 3b and the plate-shaped G1 electrode G1 on which gold has been vapor-deposited are set using a jig (not shown) to perform brazing (first brazing process). In step S3,
The cathode holder 5 holding the cathode is attached to the G1 electrode G
1 and the spacers 3a and 3b are brazed to the opposite surface (second brazing process).

Thereafter, in step S4, the cathode material is sprayed onto the sleeve 4, and in step S5, the sleeve 4 coated with the cathode material is moved to a predetermined distance (dKG in FIG. 2) between the G1 electrode G1 and the cathode surface. The cathode holder 5 is welded according to the size (sleeve attachment process). Step S6
Then, the center of the hole of the G2 electrode (second control grid) G2 and the center of the hole of the G1 electrode G1 are made to coincide with each other, and the sleeved parts (parts after the step S5) are replaced with the spacers 3a and 3b. Welding and fixing with G2 electrode G2 (second
Grid processing). In step S7, the second grid-attached product (the part for which step S6 has been completed) is fixed with multiform glass, so-called beading (beading process) together with the third to fifth control grids (not shown). Then, in step S8, the heater is inserted, the lead wire from each grid and the stem are welded, and the electron gun is completed (assembly of the electron gun).

In this embodiment, the case where gold (Au) is vapor-deposited as a substance having a high work function and a low reactivity with the cathode substance in the G1 electrode coating treatment (step S1) has been described. Not limited to Au (gold), Ni (nickel), Co (cobalt), Cd (cadmium), Sb
(Antimony), Cu (copper), Pb (lead), Bi (bismuth), Tl (thallium), Ag (silver), Pd (palladium), Pt (platinum), Ru (ruthenium), Rh
The same effect can be obtained by using (rhodium), Os (osmium), Ir (iridium), or the like. Also,
Similar effects can be obtained by forming a metal film by ion sputtering, plating, etc. instead of vapor deposition. further,
If the thickness of these metal coatings is at least 10 μm, the generation of stray electrons can be reliably suppressed.

[0016]

In the method for preventing floating electron emission from the first control electrode of the cathode ray tube according to the first aspect of the present invention, the portion of the first control electrode (G1) facing the cathode material coating surface has a high work function and a high cathode function. A material such as gold (Au) having a low reactivity with is coated by a method such as ion sputtering, vapor deposition, and plating. Therefore, even if barium adheres to the surface of the first control electrode (G1) facing the cathode and becomes barium oxide due to the oxidizing gas in the cathode ray tube, the inert metal film coated on the barium oxide causes barium oxide to exist. The reaction with the reducing agent contained in the material of the first control electrode (G1) is suppressed, the generation of floating electrons is suppressed, and the image quality on a dark screen can be improved. Further, the floating electrons generated from the first control electrode (G1) cause discharge during operation of the cathode ray tube, but adverse effects due to discharge are also suppressed.

In the method for preventing floating electron emission from the first control electrode of the cathode ray tube according to the second aspect of the present invention, Ni (nickel), which has a high work function and a low reactivity with the cathode substance,
Co (cobalt), Cd (cadmium), Sb (antimony), Cu (copper), Pb (lead), Bi (bismuth),
Tl (thallium), Ag (silver), Pd (palladium),
Pt (platinum), Ru (ruthenium), Rh (rhodium), Os (osmium), Ir (iridium), etc. are used. Even if such a substance is used, the same effect as the method for preventing floating electron emission from the first control electrode of the cathode ray tube according to claim 1 can be obtained.

In the method for preventing floating electron emission from the first control electrode of the cathode ray tube according to the third aspect of the present invention, the thickness of a material having a high work function and a low reactivity with the cathode material is set to at least 10 μm. There is. Therefore, the same effect as that of the method for preventing floating electron emission from the first control electrode of the cathode ray tube according to claim 1 can be reliably obtained.

According to a fourth aspect of the present invention, in the first control electrode, Au (gold), Ni (nickel), C having a high work function and a low reactivity with the cathode substance is provided in a portion facing the cathode substance coating surface.
o (cobalt), Cd (cadmium), Sb (antimony), Cu (copper), Pb (lead), Bi (bismuth), T
l (Thallium), Ag (Silver), Pd (Palladium), P
Substances such as t (platinum), Ru (ruthenium), Rh (rhodium), Os (osmium) and Ir (iridium) are coated by ion sputtering, vapor deposition, plating or the like. Therefore, the same effect as the method for preventing floating electron emission from the first control electrode of the cathode ray tube according to claim 1 can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a method of preventing floating electron emission from a first control electrode of a cathode ray tube according to the present invention, and a process diagram showing a process at the time of assembling an electron gun.

FIG. 2 is a schematic diagram for explaining a generation state of floating electrons in a cathode and a G1 electrode in a cathode ray tube.

[Explanation of symbols]

1 holder, 2 metal coating, 3a and 3b spacers,
4 sleeve, 5 cathode holder, G1 G1 electrode, G2 G2 electrode

Claims (4)

[Claims] 1. A material, such as Au (gold), having a high work function and a low reactivity with the cathode material, is ion-sputtered, vapor-deposited, plated at a portion of the first control electrode (G1) facing the cathode material-coated surface. A method for preventing floating electron emission, which is characterized in that coating is performed by a method such as. 2. A substance having a high work function and a low reactivity with a cathode substance is Ni (nickel), Co (cobalt), Cd (cadmium), Sb (antimony), Cu.
(Copper), Pb (lead), Bi (bismuth), Tl (thallium), Ag (silver), Pd (palladium), Pt (platinum), Ru (ruthenium), Rh (rhodium), Os
The method for preventing floating electron emission according to claim 1, wherein the method is (osmium), Ir (iridium), or the like. 3. The method of preventing stray electron emission according to claim 1, wherein a material having a high work function and a low reactivity with the cathode material is coated with a thickness of at least 10 μm. 4. The portion facing the cathode material coated surface,
Au, which has a high work function and low reactivity with cathode materials
(Gold), Ni (nickel), Co (cobalt), Cd
(Cadmium), Sb (antimony), Cu (copper), P
b (lead), Bi (bismuth), Tl (thallium), Ag
(Silver), Pd (palladium), Pt (platinum), Ru
A first control electrode, wherein a substance such as (ruthenium), Rh (rhodium), Os (osmium), Ir (iridium) is coated by ion sputtering, vapor deposition, plating or the like.