JPH08203448A - Cathode structure body of color cathode-ray tube - Google Patents

Abstract

PURPOSE: To prevent color tone disorder due to losing of white balance during a long time use by forming a slit in a flare part of a cathode substrate metal and improving the adhesion strength of the flare part to a cathode sleeve when the flare part is welded to the sleeve. CONSTITUTION: A cathode 1 is composed of a cathode sleeve 2, a cap like cathode substrate metal 3 having a slit in a flare part 30 fixed in the sleeve by welding, and an alkaline earth metal oxide 4 applied to the tip part of the cap like cathode substrate metal 3 and the cathode 1 is supported on and fixed in an insulating supporting body through a cathode supporting body 9. A heater 5 in the sleeve 2 is fixed in a heater auxiliary supporting body 6, a heater supporting body 7, and a heater connecting body 8 by welding. The slit absorbs the gap between the metal 3 and the sleeve 2, improves the adhesion strength, makes the tip part of the metal 3 flat, uniformalizes the shape, and at the same time stabilizes the degree of thermal conduction. As a result, temperature unevenness of the metal 3 compose of three pieces is eliminated and a cathode with good balance is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode assembly of a color cathode ray tube, and more particularly to an in-line type cathode assembly.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing a main part of a conventional in-line type cathode assembly. Originally, the in-line type cathode structure has three cathodes of blue, green and red supported by respective cathode supports and arranged in a straight line side by side. However, in order to simplify the explanation here, Although one cathode will be described as an example, the other two cathodes have the same structure. As shown, the cathode 11 is supported and fixed to an insulating support (not shown) via a cathode support 19. The cathode 11 includes a cathode sleeve 12, a hat-shaped cathode base metal 13 welded and fixed to the cathode sleeve 12, and an alkaline earth metal oxide 14 applied on the top of the cathode base metal 13. The heater 15 is inserted, and is welded and fixed to the heater auxiliary support 16, the heater support 17, and the heater connecting body 18.

In order to explain in more detail, FIG. 4 is a schematic view showing a fitting state of a conventional cathode sleeve and cathode base metal.
Shown in Cathode sleeve 12 and hat-shaped cathode base metal 1
3 and 3 are combined and fixed by welding, but in order to facilitate the combination, as shown in FIG.
And the clearance from the hat-shaped cathode base metal 13 is slightly increased. However, since this clearance exceeds the laser weldable region, the flare portion of the hat-shaped cathode base metal 13 is pressed against the cathode sleeve 12 side in four directions as shown by the arrow during welding. For this reason, as shown in the top view of FIG. 4B, when pressure welding is performed, the cathode base metal 13 is deformed as shown by the chain line in the figure, and as shown in FIG. The upper surface of the cathode base metal 13 bulges slightly in a convex shape, so that the alkaline earth metal oxide 1 applied to the top of the cathode base metal 13 in FIG.
The thickness of 4 differs between the central portion and the peripheral surface portion.

In operation, the reducing agent contained in the hat-shaped cathode base metal 13 which is heated by the heater 15 and welded and fixed to the top of the cathode sleeve 12 and the cathode base metal 1 are operated.
The reaction with the alkaline earth metal oxide 14 applied to the top of the No. 3 is promoted, and the hat-shaped cathode base metal 13 is changed to 700
Electrons are emitted by heating to an operating temperature of ℃ to 800 ℃. The cathode assembly of the color cathode ray tube is formed by arranging three cathode assemblies as described above side by side on a straight line.

[0005]

However, according to the conventional cathode assembly as described above, the cathode sleeve 12 and the hat-shaped cathode base metal 13 are combined and welded and fixed, but the combination is easy. Therefore, the clearance between the cathode sleeve 12 and the hat-shaped cathode base metal 13 is designed to be slightly larger. Since this clearance exceeds the laser weldable region, the flare portion of the hat-shaped cathode base metal 13 is attached to the cathode sleeve 12.
Welding is performed while applying pressure to the four sides. By this pressurization, the clearance is reduced as a whole, but the variation in fitting between the cathode sleeve 12 and the cathode base metal 13 is increased to cause an unreasonable deformation, and the top of the cathode base metal 13 is slightly convex. It will transform into a shape.

This means that the three cathode base metals 13 forming blue, green, and red and the cathode sleeve 12 have variations in their shapes after welding, and the alkaline earth metal oxide on the top of the cathode base metals. Is not uniformly coated, and the amount of heat conduction from the contact surface, which is the welded portion of the cathode base metal 13 and the cathode sleeve 12, becomes unstable, and the respective temperatures of the three cathode base metals 13 vary. It is the cause. The variation in the temperature of the three cathode base metals 13 causes a difference in the deterioration rate of the electron emission characteristics of the three cathode base metals 13, and the white balance collapses during long-term use, resulting in poor color tone. Come on. Therefore, by eliminating the variations in the shapes of the cathode base metal 13 and the cathode sleeve 12 after welding, it is desired to eliminate the variations in the temperatures of the three cathode base metals 13 and realize a temperature-balanced cathode.

[0007]

According to the present invention, a flare portion of a cathode base metal formed in a hat shape containing a reducing agent on the upper portion of the cathode sleeve is welded to the cathode sleeve, and an alkaline earth is formed on the cathode base metal. In a cathode assembly of a color cathode ray tube in which three cathodes of blue, green and red, which are coated with a metal oxide and have a heater inserted inside a cathode sleeve, are supported by respective cathode supports and arranged and fixed in a straight line. There is provided a cathode assembly of a color cathode ray tube, characterized in that the metal base metal is provided with means for adhering a welding surface of the cathode sleeve and the cathode base metal. Further, there is provided a cathode assembly of a color cathode ray tube, wherein the welding surface adhering means is a slit provided in the cathode base metal for absorbing a gap due to the clearance with the cathode sleeve.

[0008]

According to the above structure, the flare portion of the hat-shaped cathode base metal is provided with the slit, so that when the flare portion of the hat-shaped cathode base metal and the cathode sleeve are welded,
Even if the pressure is applied in four directions, the slit can absorb the gap due to the clearance between the flare portion of the cathode base metal and the cathode sleeve. Therefore, the adhesion between the cathode base metal and the cathode sleeve is improved, the top of the cathode base metal is flattened, and the shape after welding is made uniform, and the alkaline earth metal oxidation to the top of the cathode base metal is performed. The object is uniformly coated, and the amount of heat conduction from the contact surface, which is the welded portion of the cathode base metal and the cathode sleeve, is stabilized and made uniform. This makes it possible to eliminate the temperature variations of the three cathode base metals and realize a cathode with a well-balanced temperature.

[0009]

Embodiments of the present invention will be described with reference to the drawings. Originally, the in-line type cathode structure is
Three cathodes of blue, green, and red are supported by respective cathode supports and arranged side by side in a straight line, but here, in order to simplify the explanation, one cathode is described as an example. The other two cathodes have the same structure. FIG. 1 is a sectional view of a main part of a cathode assembly of a color cathode ray tube according to the present invention, and FIG. 2 is a perspective view (a) and a plan view (b) of a cathode base metal having a slit in a flare portion according to the present invention. .

In the figure, 1 is a cathode, 2 is a cathode sleeve, 3 is a cathode base metal, 30a is a slit provided in the flare portion 30 of the cathode base metal 3, and 4 is an alkaline earth metal. An oxide, and 5 is a heater. As shown in FIGS. 1 and 2, the cathode 1 is supported and fixed to an insulating support (not shown) via a cathode support 9. The cathode 1 includes a cathode sleeve 2, a hat-shaped cathode base metal 3 having a slit 30a formed in a flare portion 30 welded and fixed thereto, and an alkaline earth metal oxide applied on the top of the cathode base metal 3. The heater 5 is inserted into the cathode sleeve 2, and is fixed to the auxiliary heater support 6, the heater support 7, and the heater connecting body 8 by welding.

As shown in FIGS. 2A and 2B, the slit 30 is formed in the flare portion 30 of the cathode base metal 3.
Although four a are provided in this embodiment, for example, one to several slits may be provided depending on the size of the shape. More specifically, the cathode sleeve 2 and the hat-shaped cathode base metal 3 are combined and welded and fixed. However, in order to facilitate the combination, the cathode sleeve 2 and the hat-shaped cathode base metal 3 are designed. The clearance is slightly larger, but since this clearance exceeds the laser weldable area (about 10 μm or less), the flare portion 30 of the hat-shaped cathode base metal 3 is pressed against the cathode rib 2 side during welding. Welding while applying pressure in four directions. If the cathode base metal 3 is not provided with slits, the cathode base metal 3 and the cathode sleeve 2 as described in the prior art.
And the shape after welding will vary.

However, since the flare portion 30 of the cathode base metal 3 is provided with the slit 30a, the flare portion 30 of the cathode base metal 3 is welded when the flare portion 30 of the hat-shaped cathode base metal 3 and the cathode sleeve 2 are welded. Even if the pressure is applied to the cathode sleeve 2 in four directions, the slit 30a absorbs a gap due to the clearance between the flare portion 30 of the cathode base metal 3 and the cathode sleeve 2. Therefore, the adhesion between the cathode base metal 3 having the slits 30a and the cathode sleeve 2 is improved, and the cathode base metal 3 is
Of the cathode base metal 3 becomes flat, the shape after welding is made uniform, and the top of the cathode base metal 3 is uniformly covered with the alkaline earth metal oxide 4, and the cathode base metal 3 and the cathode sleeve 2 are The amount of heat conduction from the contact surface, which is the welded portion, is stabilized and uniformized. The cathode assembly of the color cathode ray tube is formed by arranging three cathode assemblies as described above side by side on a straight line.

[0013]

As described above, according to the cathode assembly of the color cathode ray tube of the present invention, the slit is provided in the flare portion of the cathode base metal, so that when the cathode base metal and the cathode sleeve are welded, they are welded. The subsequent shape is made uniform. This improves the adhesion between the cathode base metal and the cathode sleeve, and stabilizes the heat conduction between the cathode base metal and the cathode sleeve.
Moreover, the top of the cathode base metal is flattened, and the top of the cathode base metal is uniformly coated with the alkaline earth metal oxide. As a result, there was no variation in the temperature of the three cathode base metals, and a cathode with a well-balanced temperature was realized. That is, by reducing the difference in the deterioration rates of the three electron emission characteristics of blue, green, and red, the problem that the white balance collapses and the color tone deteriorates even after long-term use is solved.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a cathode assembly of a color cathode ray tube showing an embodiment of the present invention.

FIG. 2 is a perspective view (a) and a plan view (b) of a cathode base metal provided with a slit according to the present invention.

FIG. 3 is a sectional view of a main part of a cathode assembly of a conventional cathode ray tube.

FIG. 4 is a schematic view showing a fitting state of a conventional cathode sleeve and cathode base metal.

[Explanation of symbols]

 1 Cathode 2 Cathode Sleeve 3 Cathode Base Metal 4 Alkaline Earth Metal Oxide 5 Heater 6 Heater Auxiliary Support 7 Heater Support 8 Heater Connection Support 9 Cathode Support 30 Flare 30a Slit

Claims (2)

[Claims] 1. A flare portion of a cathode base metal which is formed in a hat shape and includes a reducing agent on the upper portion of the cathode sleeve is welded to the cathode sleeve, and the cathode base metal is coated with an alkaline earth metal oxide. In the cathode assembly of the color cathode ray tube, the three cathodes of blue, green, and red, in which heaters are inserted inside the cathode sleeve, are supported by respective cathode supports and arranged and fixed in a straight line. A cathode assembly of a color cathode ray tube, further comprising: means for adhering a welding surface between the cathode sleeve and the cathode base metal. 2. A cathode assembly of a color cathode ray tube, wherein the welding surface adhering means is a slit provided in the cathode base metal.