JPH10289670A - Cathode-ray tube and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent barium from being stuck to a first grid and prevent the deterioration of a level of stray emission by covering an oxide film composed of a material of a first grid electrode on, at least, a part of an electron transmission hole of the first grid electrode arranged adjacent to a cathode. SOLUTION: A first grid electrode 12 is provided with an electron beam transmission hole 12a with a shaft set as the central axis formed therein and an oxide film 15 composed of a material of the first grid electrode 12 is formed around the electron beam transmission hole 12a and its surrounding. A second grid electrode 13 is also provided with an electron beam transmission hole 13a with a shaft set as the central axis formed therein. The electron beam 16 is emitted from an electron emission material layer 11C heated by a heater 11A and made to irradiate a phosphor surface side through the electron beam transmission hole of each grid electrode. Barium is emitted from the electron emission material layer 11C and if it is applied on the first grid electrode 12, the oxide film 15 of the first grid electrode 12 prevents it from being stuck thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube and a method of manufacturing the same, and more particularly, to a cathode ray tube having an improved electron gun structure and a method of manufacturing the same.

[0002]

2. Description of the Related Art During the manufacturing process of a cathode ray tube, for example, during aging or raster running, barium evaporated from the cathode of an electron gun assembly adheres to a first grit electrode, and this barium becomes an emission source. It is known that unnecessary electrons are emitted.

In such a case, a phenomenon occurs in which a spot-shaped luminescent spot remains at the center of the display section even if the image being displayed is erased.

Therefore, conventionally, a so-called knocking process for removing the above-mentioned emission source by electric shock due to a spark by applying a high voltage directly to a second grid electrode which is adjacent to and opposed to the first grid electrode of the electron gun structure is conventionally performed. It is usually done.

[0005]

However, even if the emission source is removed by such a knocking process, for example, during the subsequent operation of the cathode ray tube, the first
Barium also adheres to the grid electrode, causing a problem of deterioration of the so-called strain emission level.

[0006] Here, the strain emission refers to a potential difference between the second grid electrode and the first grid electrode, which is sufficient for emission of unnecessary electrons by the emission source.

[0007] For this reason, the knocking treatment has been practically ineffective in removing the emission source (however, it is extremely effective in removing burrs generated on a grit electrode formed by pressing). .

The present invention has been made in view of such circumstances, and an object of the present invention is to prevent barium from adhering to the first grid electrode and prevent the level of strain emission from deteriorating. An object of the present invention is to provide a cathode ray tube having an electron gun assembly and a method of manufacturing the same.

[0009]

The following is a brief description of an outline of a typical invention among the inventions disclosed in the present application.

Means 1. A cathode ray tube having an electron gun assembly having a cathode and a plurality of grid electrodes coaxially, wherein at least an electron transmission hole of a first grid electrode of each of the grid electrodes which is arranged adjacent to the cathode. An oxide film made of the material of the first grid electrode is applied to the portion.

Since an oxide film is formed on at least the electron transmission holes of the first grid electrode, even if barium adhered to the first grid electrode functions as an emission source by the insulating oxide film. Disappears.

Therefore, deterioration of the level of the strain emission does not occur.

Further, since the oxide film is made of the material of the first grid electrode, there is an effect that its formation is extremely simple.

Means 2. In a method of manufacturing a cathode ray tube including a cathode and an electron gun structure having a plurality of grid electrodes along a same axis, a G1 baking process for removing gas adhering to the grid electrodes and a method of activating the cathodes And a step after the G1 baking step,
A period in which the heating temperature required in the G1 baking step is reduced is provided, and thereafter, an activation step is performed.

In this case, it is confirmed that CO ₂ generated in the activation step has reached a temperature at which an oxide film can be formed by reacting with the material constituting the first grid electrode.

As described above, even if barium adheres to the first grid electrode, this oxide film can hinder its function as an emission source.

Incidentally, conventionally, conventionally, G1
Since the baking process and the activation process are partially overlapped with each other, and the temperature of the first grid electrode was too high at the activation stage, CO ₂ reacts with the material of the first grid electrode. No oxide film was formed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cathode ray tube according to the present invention and a method for manufacturing the same will be described below with reference to the drawings.

FIG. 2 is a sectional view showing a schematic structure of a cathode ray tube to which the present invention is applied.

In FIG. 1, there is a vacuum envelope 1 made of glass. The envelope 1 has a face panel 1A having a flat surface on the side where a display is viewed.
A neck portion 1B enclosing the electron gun structure 2 disposed to face the face panel portion 1A; and a neck portion 1B.
B and a funnel section 1C for smoothly connecting the face panel section 1A.

The electron gun assembly 2 is composed of three electron guns having the same configuration, which are arranged and integrated in the y direction in the drawing. Each electron gun is for red (R) and green ( G) and blue (B).

Each electron beam (not shown) from each of the electron guns of the electron gun assembly 2 is driven by a deflection yoke 4 arranged on the outer periphery of a portion of the funnel portion 1C close to the neck portion 1B. It is to be scanned.

In this case, the scanning in the x direction is sequentially repeated in the z direction, so that the inner wall surface of the face panel portion 1A is uniformly distributed from the upper left (as viewed from the face panel portion 1A side) to the lower right. It is coming.

Further, on the inner wall surface of the face panel section 1A on which the electron beam is scanned as described above, a phosphor that emits light by the projection of the electron beam is applied to form a phosphor surface 5.

The phosphor surface 5 is composed of a phosphor exhibiting red (R), a phosphor exhibiting green (G), and a phosphor exhibiting blue (B). They are arranged adjacent to each other, and such an arrangement is made over the entire area of the face panel unit 1. That is, of the innumerable pixels constituting the display unit, one pixel for color is constituted by adjoining the phosphors exhibiting the respective colors.

As described above, one pixel for color is irradiated with each electron beam scanned from the electron gun assembly 2, and each electron beam emits a red (R) light beam constituting one pixel. , A green (G) phosphor, and a blue (B) phosphor.

In this case, each of the electron beams is directed to the corresponding one of the electron transmission holes of the shadow mask 7 which is arranged to face the phosphor surface 5 and has an electron transmission hole formed in correspondence with each of the color pixels. , And accurately and reliably strike each of the phosphors exhibiting each color through the light.

FIG. 1 is a diagram showing the configuration of one of the electron guns constituting the electron gun configuration 2 (the same applies to other electron guns). FIG. 4 is a cross-sectional view showing details of a certain cathode, a first grid electrode, and a second grid electrode.

In the figure, the cathode 1 is arranged coaxially.
1, first grid electrode 12 and second grid electrode 13
Are sequentially arranged.

The cathode 11 has a cylindrical sleeve 11B which has a heater 11A built-in and whose central axis is aligned with the axis of the heater 11A. The sleeve 11B has an end closed at the first grid electrode 12 side. Have. An electron emission material layer 11C is formed on the closed end face of the sleeve 11B.

The electron emission material layer 11C is made of, for example, an alkaline earth metal oxide containing Ba.

The first grid electrode 12 is formed with an electron beam transmitting hole 12a having the axis as a central axis, and the electron beam transmitting hole 12a and its surroundings are formed by oxidation of the material of the first grid electrode 12. A film 15 is formed.

Further, similarly to the first grid electrode 12, the second grid electrode 13 has an electron beam transmitting hole 13a having the axis as a central axis.

In such a configuration, the electron beam 16 is emitted from the electron-emitting material layer 11C heated by the heater 11A, and the first grid electrode 12, the second grid electrode 13, and the next grid electrodes (not shown) are formed. Irradiation is performed on the phosphor surface 5 through the electron beam transmitting holes 12a and 13a.

At this time, the electron-emitting material layer 11C moves from the Ba
Is released and adheres to the first grid electrode 12,
The insulating oxide film 15 formed on the Baf first grid electrode 12 does not function as an emission source.

Therefore, deterioration of the level of the strain emission does not occur.

Next, one embodiment of a method of manufacturing the cathode ray tube thus constituted will be described with reference to FIG.

In manufacturing the cathode ray tube, after the electron gun assembly 2 is inserted into the envelope 1 from the neck 1B, the envelope 1 is evacuated from the neck 1B. Because of this, the gas in the envelope 1 is exhausted through the electron gun assembly 2,
The gas comes to adhere to the electron gun assembly 2.

In order to remove this gas, heating called G1 baking is performed at about 680 ° C.

Then, as a subsequent step, the cathode 1
In order to activate one electron-emitting material layer 11C, a current is supplied to the heater 11A to heat the electron-emitting material layer 11C.

If the activation is not performed, the electron beam 16 is not emitted from the cathode 11 even if the commercialized cathode ray tube is driven.

Here, in this embodiment, in particular, in the case of performing this activation, a blank period is provided after performing the G1 baking, so that the temperature of the atmosphere near the electron gun assembly 2 is reduced. Is to do.

By doing so, the temperature required for activation can be set in the range of 200 ° C. to 400 ° C., and CO _{2 in} the atmosphere reacts with the material of the first grid electrode 12 to form an oxide film on the surface. Can be formed.

The temperature of the atmosphere in the vicinity of the electron gun assembly 2 gradually increases as shown in the figure to maintain a constant temperature, but the temperature is in the range of 200 ° C. to 400 ° C. This is the portion indicated by Q.

Here, the oxide film can be formed even when the temperature required for activation is 200 ° C. or lower, but it is preferable to set it to 200 ° C. or higher because the oxide film is easily peeled off.

Incidentally, conventionally, as apparent from FIG. 4 corresponding to FIG. 3, the G1 baking process and the activation process are conventionally partially overlapped with each other. In the activation stage, the heating temperature of the G1 baking is greatly affected, and the temperature of the first grid electrode 12 is too high. For this reason, CO ₂ does not react with the material of the first grid electrode, and an oxide film is formed. I didn't.

FIG. 5 is a graph showing the results of quantitative evaluation of the cathode ray tube according to the present embodiment. First, the level of the strain emission is quantified by the electrode potential difference where the strain starts to occur as shown in the figure.

As shown in the figure, in the conventional technique, the technique of the present embodiment, and the technique of activating the first grid electrode 12 at a low temperature, the strain generation voltage of the cathode ray tube manufactured by each method is reduced. It was measured and evaluated.

Here, the temperature of the first grid electrode 12 at the time of activation in the conventional technique is 400 ° C. to 600 ° C., and the temperature of the first grid electrode 12 in the technique of the present embodiment is 20 ° C.
The temperature of the first grid electrode 12 in the technique of activating at a low temperature of 0 ° C. to 400 ° C. is 200 ° C. to normal temperature.

As a result of this evaluation, the lower the temperature of the first grid electrode 12 at the time of activation is, the higher the level of the strain emission is, but a great side effect is caused with respect to the first grid electrode 12.

From this, it is clear that the temperature of the first grid electrode at the time of activation is in the range of 200 ° C. to 400 ° C. without any side effects and obtaining a great effect on the strain emission.

In the above embodiment, a blank period is provided after the G1 baking is performed, so that the temperature of the atmosphere near the electron gun assembly 2 is reduced. However, the present invention is not limited to providing the blank period, and it goes without saying that the temperature of the atmosphere near the electron gun assembly 2 may be forcibly reduced.

The point is that C generated when the cathode is activated is
It is sufficient that O ₂ reacts with the material of the first grid electrode disposed adjacent to the cathode to reach a temperature at which an oxide film can be formed.

[0054]

As is apparent from the above description,
According to the cathode ray tube and the method of manufacturing the same according to the present invention, it is possible to obtain an electron gun assembly that prevents barium from adhering to the first grid electrode and does not cause deterioration in the level of strain emission. .

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing one embodiment of an electron gun of a cathode ray tube according to the present invention.

FIG. 2 is a schematic sectional view showing one embodiment of a cathode ray tube according to the present invention.

FIG. 3 is an explanatory view showing one embodiment of a method for manufacturing a cathode ray tube according to the present invention.

FIG. 4 is an explanatory view showing an example of a conventional method for manufacturing a cathode ray tube.

FIG. 5 is a graph showing the effect of the cathode ray tube according to the present invention.

[Explanation of symbols]

11: cathode, 12: first grid electrode, 12a
... Electron beam transmission hole, 13 ... Second grid electrode, 1
3a: electron beam transmission hole, 15: oxide film.

Claims (4)

[Claims] 1. An electron gun assembly having a cathode and a plurality of grid electrodes coaxially, and at least the electron transmission of a first grid electrode of each of the grid electrodes arranged adjacent to the cathode. A cathode ray tube, wherein an oxide film made of the material of the first grid electrode is applied to a portion of the hole. 2. A method for manufacturing a cathode ray tube comprising a cathode and an electron gun assembly having a plurality of grid electrodes along a coaxial axis, wherein CO ₂ generated upon activation of the cathode is adjacent to the cathode. A method for producing a cathode ray tube, wherein the temperature is adjusted to a temperature at which an oxide film is formed by reacting with a material of a first grid electrode arranged in a vertical direction. 3. A G1 baking step for removing gas adhering to the grid electrode, and a step of activating a cathode, and after the G1 baking step, the heating required in the G1 baking step is performed. Set a period to reduce the temperature,
3. An activation step is performed thereafter.
The method for manufacturing the cathode ray tube according to the above. 4. The temperature at the time of activation is 200 ° C. to 40 ° C.
4. The method according to claim 2, wherein the temperature is in a range of 0 ° C.
The method for manufacturing the cathode ray tube according to the above.