JPH06162947A - Cathode body structure for cathode-ray tube - Google Patents

Abstract

PURPOSE:To unify the temperature of three cathode base metals, regarding a cathode body structure of an in-line type color cathode-ray tube. CONSTITUTION:Regarding a cathode structure body where three cathodes for blue, green and red are respectively laid and fixed along a straight line, while being supported on cathode supports 18a, 18b and 18c, the intermediate cathode is positioned lower than the cathodes at both sides by the predetermined distance, and heat radiated from both cathodes to the intermediate cathodes is shielded with the supports 18a, 18b and 18c, thereby unifying the temperature of cathode base metals 12a, 12b and 12c. Also, the section 19A of a G1 electrode is projected toward the cathodes for preventing even a drop in cutoff voltage.

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 picture tube, and more particularly to a cathode assembly of an in-line type color picture tube.

[0002]

2. Description of the Related Art Conventionally, the cathode structure of a color picture tube is blue,
The three cathodes, green and red, are supported by each cathode support and arranged and fixed in a straight line, so the cathode in the center receives heat conduction and heat radiation from the cathodes on both sides, and the cathode substrate The temperature of the metal is generally higher than the temperatures of the cathode base metals located on both sides, the electron emission characteristics deteriorate rapidly, and there is a problem that a change in color tone called white balance collapse occurs during long-term use.

FIG. 3 is a sectional view showing an example of the structure of a conventional cathode. The respective cathodes for blue, green and red are the cathode sleeves 11 provided inside the cathode supports 18a, 18b and 18c.
A base metal 12a, 12b, 12c, which is shaped like a cap having the same plate thickness and is arranged to face the G1 electrode 19 at a predetermined distance, is welded on a, 11b, 11c, and an alkaline earth oxide is formed thereon. 13a, 13b, 13c are covered. Heaters 14a, 14b, 14c are inserted in the cathode sleeves 11, 11b, 11c, and heater auxiliary supports 15a, 15b, 15c, heater supports 16a, 16b, 16c, heater connecting body 17a,
It is supported and fixed by 17b and 17c, electric power is supplied through them, and the base metal 12a, 12b and 12c is
It is heated so as to reach 00 to 800 ° C.

At this operating temperature, the base metals 12a, 12b,
Reducing agents such as Mg and Si contained in 12c are diffused on the surface and coated with alkaline earth metal oxides 13a, 13
Electrons are emitted for a long time by the reaction with b and 13c.

[0005]

As described above, in the cathode structure of the conventional color picture tube, the three cathodes for blue, green, and red are arranged and fixed in a straight line, so that among the three cathodes. The temperature of the base metal 12b of the cathode becomes higher than the base metal 12a, 12c of the cathodes on both sides by about 5 to 10 ° C. due to the heat radiation of the cathodes located on the both sides, and the center cathode is included in the base metal 12b. Since the diffusion rate of the reducing agent such as Mg and Si increases and the consumption becomes severe, the electron emission characteristics of the cathode begin to deteriorate earlier than the cathodes on both sides.
There was a problem such as a change in color tone called white balance loss during long-term use.

[0006]

In the cathode assembly of the color picture tube of the present invention, a cap-shaped base metal containing a reducing agent is welded to the upper part of the cathode sleeve, and an alkaline earth metal oxide is deposited on the base metal. In the cathode assembly of a color picture tube, three cathodes for blue, green, and red, which are covered and have a heater inserted inside the cathode sleeve, are supported by respective cathode supports and arranged and fixed in a straight line, Of the three cathodes, the position of the cathode located at the center is lower than the positions of the cathodes located on both sides, and preferably, in order to correct the cutoff, the portion of the G1 electrode facing the central cathode is placed on the cathode side. The cathode is made to be convex by an amount lowered, or the plate thickness is made smaller.

[0007]

According to the above construction, since the cathode located at the center is located lower than the cathodes located on both sides, the shielding effect of the cathode support reduces the amount of heat radiation received from the cathodes on both sides, and the cathode substrate The temperature of the metal becomes almost the same as the temperature of the cathode base metal on both sides, and the cutoff voltage is lowered by lowering the cathode by making the shape of G1 convex by the amount of lowering the cathode, or It is also possible to correct by making the thick plate small, and it is possible to prevent the white balance from breaking down during long-term use.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view of a cathode assembly according to an embodiment of the present invention. In the figure, the same parts as those of the conventional example of FIG.

The three cathodes for blue, green and red are supported by respective cathode supports 18a, 18b and 18c and arranged and fixed in a straight line. The cathode located in the center is welded and fixed at a position lower than the cathodes located on both sides, and the shape of the G1 electrode 19A portion facing the cathode located in the center is convex on the cathode side.

According to this embodiment, since the cathode located at the center is lower than the cathodes located on both sides,
Due to the shielding effect of the cathode supports 18a, 18b, 18c,
The heat radiation received from both sides is reduced, and the central cathode substrate 12
There is an advantage that the temperature of b can be lowered.

[0012]

[Embodiment 2] FIG. 2 is a longitudinal sectional view of a cathode assembly according to another embodiment of the present invention.

In this embodiment, the G1 electrode facing the cathode in the center of the first embodiment is replaced with a G1 electrode 19A having a convex shape, and a G1 electrode 19B having a reduced plate thickness is used. Since it is the same as that of the first embodiment, the same parts are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, as in the case of FIG. 1, since the central cathode is located lower than the cathodes located on both sides, the heat received from both sides is generated by the shielding effect of the cathode supports 18a, 18b, 18c. The cutoff voltage is reduced because the radiation is reduced and the plate thickness of the G1 electrode 19B portion corresponding to the central cathode is made thinner than the plate thickness of the G1 electrode 19B portion facing the cathodes on both sides. Can be prevented.

[0015]

As described above, according to the present invention, blue, green,
Three cathodes for red are supported by respective cathode supports and arranged and fixed in a straight line. In the cathode assembly of the color picture tube, the central cathode of the three cathodes is located on both sides. By lowering by a predetermined amount compared to the cathode and reducing the heat radiation received from the cathodes on both sides, by making the temperature of the central cathode substrate metal similar to the cathodes located on both sides,
It is possible to obtain a highly reliable cathode assembly for a cathode ray tube that does not cause a change in color tone such as a loss of white balance during long-term use.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a cathode assembly for a cathode ray tube according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a cathode structure for a cathode ray tube which is another embodiment of the present invention.

FIG. 3 is a vertical sectional view of a conventional cathode structure for a cathode ray tube.

[Explanation of symbols]

 11a, 11b, 11c Cathode sleeve 12a, 12b, 12c Cathode base metal 13a, 13b, 13c Alkaline earth metal oxide 14a, 14b, 14c Heater 15a, 15b, 15c Heater auxiliary support 16a, 16b, 16c Heater support 17a , 17b, 17c Heater connection body 18a, 18b, 18c Cathode support body 19A, 19B G1 electrode

Claims (3)

[Claims] 1. A blue base metal comprising a reducing agent and a cap-shaped base metal fixed to the upper portion of the cathode sleeve, coated with an alkaline earth metal oxide, and having a heater inserted inside the cathode sleeve. In the cathode structure of a color picture tube in which three cathodes for green and red are supported by respective cathode supports and arranged and fixed in a straight line, the center cathode is lowered relative to the cathodes on both sides. A cathode assembly for a cathode ray tube. 2. The cathode assembly for a cathode ray tube according to claim 1, wherein the G1 electrode facing the central cathode is convex toward the cathode. 3. The cathode assembly for a cathode ray tube according to claim 1, wherein a plate thickness of a G1 electrode portion facing the central cathode is reduced.