JPH07105833A - Color cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent the defect of a cathode and prevent a reduction in emission by forming a getter material arranged in a color cathode-ray tube by pulverizing, mixing and pressing its component in helium atmosphere. CONSTITUTION:An electron gun body structure 8 having a cathode 8A installed thereto is arranged in the end part of the neck part 7 of the envelop 30 of a color cathode-ray tube, and a getter body 9 to be connected thereto through a leaf spring 15 is arranged in a funnel part 6. The getter body 9 is formed by housing a getter material mainly consisting of Ba in a cup vessel, and the tube inner part is held at a prescribed reduced pressure value. The getter material is formed by pulverizing, mixing and pressing its component in He atmosphere. The residual gas in the tube is thus mostly occupied by He having a low atomic weight, and even when it is ionized by an electron beam and collided, the impact to the cathode 8A is extremely minimized, and the cathode 8A is never damaged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly to improvement of a getter material arranged in the tube.

[0002]

2. Description of the Related Art The inside of a color cathode ray tube is maintained at a predetermined decompression value.

In order to keep the inside of the color cathode ray tube at a predetermined reduced pressure value, a getter material containing barium as a main component is placed in the tube during the manufacturing process thereof, and after the tube is exhausted. The getter material is heated and scattered. This is because such a getter material has a gas absorbing ability.

The getter material was formed by pressing an alloy of barium and aluminum into powder in the air and mixing it with nickel powder.

In recent years, a so-called impregnated cathode has been widely used as the cathode of the color cathode ray tube.

This impregnated cathode has a structure in which a porous substrate made of, for example, tungsten is impregnated with an electron emitting substance made of a barium compound, whereby a high current density and a long life can be achieved. Further, it is known that a thin film mainly composed of scandium is formed on the surface of the porous substrate to further increase the current density.

[0007]

However, in the color cathode ray tube having such a structure, a defect occurs in the scandium thin film formed on the surface of the porous substrate of the cathode, which causes a rapid decrease in emission. Came to be confirmed.

As a result of investigating the cause, it was found that 80 to 90% of the residual gas in the tube was argon gas, and this argon gas was ionized by the electron beam and collided with the scandium thin film. The reason for the large amount of argon in the residual gas is that argon is predominantly present in the atmosphere in a larger amount as compared with helium as an inert gas.

Therefore, the present invention has been made under such circumstances, and the object of the present invention is to prevent the occurrence of defects in the cathode, thereby preventing the emission from decreasing. It is to provide a color cathode ray tube.

[0010]

In order to achieve such an object, the present invention basically provides a color cathode ray tube in which a getter material is arranged in the tube, wherein the getter material contains helium as its component. It is characterized by being crushed, mixed and pressed in an atmosphere of (He).

[0011]

In the color cathode ray tube having such a structure, the getter material arranged in the tube is formed by processing its components in a helium atmosphere.

Therefore, the residual gas in the tube after the getter material is scattered is mostly occupied by helium. Since the atomic weight (mass number) of helium is extremely smaller than that of argon, even if the helium is ionized by the electron beam and collides with the cathode, its momentum is small and therefore the impact on the cathode is extremely small.

Therefore, the cathode does not have any defect, and it is possible to prevent the emission from decreasing from the surface.

[0014]

FIG. 2 is a sectional view showing the overall construction of an embodiment of the color cathode ray tube according to the present invention.

In the figure, there is an electron gun assembly 8 which emits electrons as a beam. The electron gun assembly 8 has an integrated structure of R (red), G (green), and B (blue) electron guns, and the electron beams are emitted from the respective electron guns.

Further, a fluorescent screen 2 is arranged so as to face the electron gun assembly 8, and the fluorescent screen 2 is provided with regions of respective pixels arranged in a matrix.

Areas corresponding to one pixel of the fluorescent screen 2 are irradiated with an electron beam to produce R (red) and G, respectively.
Each of the phosphors that emits (green) and B (blue) is provided adjacent to each other. In one pixel configured in this way, the amount of the electron beam from each electron gun of the electron gun assembly 8 will be described later. A predetermined color is exhibited by irradiating the corresponding phosphors under the control of the shadow mask 4 that operates.

The electron gun structure 8 and the fluorescent screen 2 are enclosed by an envelope 30 made of glass,
The phosphor surface 2 is attached to and disposed on the inner wall surface of a portion of the envelope 30 called the panel portion 1. Here, the panel portion 1 serves as a display portion of the cathode ray tube, and an observer can recognize the color development of the phosphor screen 2 through the panel portion 1.

The portion of the envelope 30 that encloses the electron gun assembly 8 is called a neck portion 7, and the portion between the neck portion 7 and the panel portion 1 is called a funnel portion 6.

A deflection yoke (not shown) is arranged on the outer periphery of the funnel portion 6 of the envelope 30, and the deflection yoke causes the electron beam from the electron gun assembly 8 to pass through the fluorescent screen 2.
Scanning (deflection) for sequentially irradiating each pixel above is performed.

The envelope 3 in the funnel portion 6
Inside 0, an internal magnetic shield 5 is arranged so as to surround a region where the electron beam is deflected.

Further, in the envelope 30 of the panel portion 7,
R, G, respectively, of the respective scanned electron beams from the respective electron guns constituting the electron gun assembly 8 to the corresponding phosphors.
A shadow mask 4 for controlling the light emission of B is arranged so as to face the phosphor screen 2.

That is, the shadow mask 4 is made of a thin plate material having an opening provided so as to face each pixel on the phosphor screen 2, and corresponds to each electron beam from each electron gun through the opening. Only the components that cause the color phosphors to emit light are allowed to pass through.

FIG. 1 is a detailed configuration diagram showing the vicinity of the electron gun 8. In the figure, a leaf spring 15 attached to the electron gun 3 extends to the funnel portion 6 side along the inner wall surface of the envelope 30, and a getter body 9 is attached to the tip of the leaf spring 15. ing.

The getter body 9 has a cup-shaped container in which the sintered getter material is housed.

The getter material is mainly composed of barium (usually an alloy with Al), and the powder is further mixed with Ni powder in an atmosphere of helium (He). The container is pressed and solidified. Since helium is one of the inert gases, it does not impair the gas-absorbing ability of the getter material at all, and does not contain extra gas such as argon.

The electron gun 3 is composed of a cathode 8A that emits electrons, and a plurality of grid electrodes arranged in parallel to guide the electrons emitted from the cathode 8A to the phosphor screen 2 side as an electron beam. It has become a thing.

FIG. 3 is a sectional view showing details of the cathode 8A incorporated in the electron gun 8.

The cathode 8A in the figure is a so-called impregnated cathode. That is, there is a cylindrical sleeve 25, and the sleeve 25 has a built-in heater 26 that is inserted and arranged from one open end thereof.

Further, at the other open end of the sleeve 25, a cathode pellet 23 arranged so as to close this open portion is mounted.

The cathode pellet 23 is housed in a cup-shaped barrier layer 24 fitted in a sleeve 25,
It is mounted on the sleeve via the barrier layer 24.

The cathode pellet 23 is made of a porous substrate obtained by press-sintering tungsten powder having an average particle size of about 5 μm.
Electron emitting material 2 composed of aO ・ CaO ・ Al ₂ O ₃
2 is impregnated. A mixed thin film layer 27 made of scandium, tungsten, oxygen or the like is formed on the open surface of the cathode pellet 23.

In the production of the color cathode ray tube thus constructed, the inside of the tube (envelope 30) is made to be 10 to ⁴ to 10 by using, for example, a rotary pump and a diffusion pump.
The air is exhausted to the order of ⁵ torr, and then the exhaust port is sealed. Further, the getter material 9 is scattered by high-frequency heating. That is why this type of getter is called a scattered getter.

As a result, the residual gas in the pipe is absorbed by the getter, and finally the inside of the pipe is 10 to ⁶ to 10 to ⁷ t.
It is designed to have a vacuum degree of the orr level.

In the color cathode ray tube having such a structure, the getter material arranged in the tube is formed by processing its components in a helium atmosphere.

Therefore, most of the residual gas in the tube is occupied by helium. However, since the atomic weight (mass number) of helium is extremely smaller than that of argon, even if helium is ionized by an electron beam,
Even when it collides with A (particularly, the mixed thin film layer 27), the impact on the mixed thin film layer 27 is extremely small because its momentum is small.

Therefore, the mixed thin film layer 27 does not have a defect, and the emission from the surface can be prevented from being lowered.

In the above-described embodiments, the impregnated cathode is used as the cathode, and the scandium thin film is formed on the surface of the impregnated cathode. However, the present invention is not limited to this, and it goes without saying that other thin films such as an osmium film may be formed.

In the above-mentioned embodiment, the impregnated cathode is used as the cathode, but the cathode is not limited to this impregnated cathode. It goes without saying that a so-called oxide cathode in which a powder sintered body of an oxide such as barium, calcium or aluminum is provided on a substrate such as nickel.

Further, in the present embodiment, the getter material is processed in a helium atmosphere, but the getter material is not limited to this and the same effect can be obtained even if the getter material is processed in a substantially complete vacuum. It goes without saying that it will be done.

[0041]

As is apparent from the above description,
According to the color cathode ray tube of the present invention, it is possible to prevent the occurrence of defects in the cathode and thereby prevent the emission from decreasing.

[Brief description of drawings]

FIG. 1 is an explanatory view of essential parts showing an embodiment of a color cathode ray tube according to the present invention.

FIG. 2 is an overall configuration diagram showing an embodiment of a color cathode ray tube according to the present invention.

FIG. 3 is a configuration diagram showing an embodiment of a cathode of a color cathode ray tube according to the present invention.

[Explanation of symbols]

 8 electron gun 8A cathode 9 getter body

Claims (1)

[Claims] 1. A color cathode ray tube in which a getter material is arranged in the tube, wherein the getter material is obtained by crushing, mixing and pressing the components in a helium atmosphere. tube.