JPH06162948A - Cathode body structure for color cathode-ray tube - Google Patents

Abstract

PURPOSE:To unify the temperature of a cathode at an intermediate position and cathodes located at both sides thereof, regarding a cathode body structure for a color cathode-ray tube where three cathodes are laid along a straight line. CONSTITUTION:In this cathode structure body, three cathodes with heaters 4a, 4b and 4c inserted in cathode sleeves 1a, 1b and 1c are laid along a straight line, while being respectively supported on heater auxiliary supports 5a, 5b and 5c. Regarding the three cathodes, the heater auxiliary support 5b at an intermediate position is made to have a larger area or thickness than other auxiliary supports 5a and 5c positioned at both sides thereof to increase a heat conduction amount from the heater 4b, thereby unifying the temperature of the three cathodes. According to this construction, the collapse of white balance during service over a long term can be prevented.

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 their respective cathode supports and are 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, The temperature of the base metal is generally higher than the temperature of the base metal of the cathodes located on both sides, and the deterioration of the electron emission characteristics of the cathode is particularly rapid, which causes a change in color tone called white balance breakdown during long-term use. There was a problem.

FIG. 4 is a sectional view showing an example of the structure of a conventional cathode.

Each of the cathodes for blue, green and red has a base metal 42 on top of the cathode sleeves 41a, 41b and 41c.
a, 42b, 42c are welded, and the base metal 42a,
42b and 42c, alkaline earth metal oxide 43a,
43b and 43c are covered. Cathode sleeve 41
heaters 44a, 44b, 4 inside a, 41b, 41c.
4c is inserted, and heater auxiliary supports 45a, 45
b, 45c and heater supports 47a, 47b, 47c are supported and fixed, an electric current is supplied through these, and the base metals 42a, 42b, 42c are heated to 700 to 800 ° C.

At this operating temperature, the base metals 42a, 42b,
The reducing agents such as Mg and Si contained in 42c are diffused on the surface and coated with the alkaline earth metal oxides 43a and 43a.
Electrons are emitted for a long period of time by the reaction with b and 43c (JP-A-3-257741 and JP-A-3-64).
823, and JP-A-3-64824).

[0006]

By the way, in the cathode structure of the conventional color picture tube described above, three cathodes for blue, green and red are arranged on a straight line. For this reason, the cathode located in the center is caused by the heat conduction and radiation of the cathodes located on both sides.
The temperature of the cathode base metal 42b is the base metal 42a, 4
The temperature becomes higher than the temperatures of 2b and 42c by about 10 ° C., so that the electron emission characteristics of this cathode begin to deteriorate earlier than the cathodes on both sides, and a change in color tone called white balance collapse occurs during long-term use. Further, there is a problem that the electron emission characteristic of only the central cathode is deteriorated by long-term use.

[0007]

The cathode assembly of the present invention comprises:
The heater auxiliary support located in the center has a large area or a thick wall, or is additionally corrugated, or two sheets are used and sandwiched between the heaters, and their volumes are located on both sides. It is larger than the body.

[0008]

According to the above construction, the amount of heat conduction is increased by increasing the volume of the central heater auxiliary support through which the heat generated by the heater is conducted. Further, since the amount of heat conduction becomes large, the temperature of the base metal in the central cathode can be lowered as compared with the conventional case, and the temperature can be made the same as that of the cathodes on both sides.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a cathode assembly showing an embodiment of the present invention. In the figure, 1a, 1b, 1c are cathode sleeves, 2a, 2b, 2c are base metals, 3a, 3
b, 3c are alkaline earth metal oxides, 4a, 4b, 4c
Is a heater, 5a, 5b and 5c are heater auxiliary supports, 6
Reference numerals a, 6b and 6c are heater support members, and 7a, 7b and 7c are heater connection members.

Next, the operation of the cathode assembly of the above invention will be described. According to this embodiment, the three heaters 4a, 4
Although the amount of heat generated from each of b and 4c is uniform, the area of the heater auxiliary support 5b at the center is increased or the thickness is made thicker so that the heater auxiliary support 5a, 5b at both ends is deposited.
By making it larger than 5c, heat conduction from the heater 4b becomes large. Due to this, conventionally, the temperature of the central basic attribute 2b is 10 ° C. higher than that of the base metal 1a, 2c at both ends.
There is an advantage that the one that is higher in the front and rear can be made to have the same temperature as the one that is at both ends and that the change in the color tone, which is called white balance collapse during long-term use, can be suppressed.

[0012]

[Embodiment 2] FIG. 2 is a perspective view of a heater auxiliary support portion in the center of a cathode assembly according to a second embodiment of the present invention.

This embodiment is the same as the first embodiment except that the central heater auxiliary support of the first embodiment is replaced with a parallel plate-shaped heater auxiliary support. The same reference numerals are given to the parts and the description thereof will be omitted.

In this embodiment, since the central heater auxiliary support 15b has a parallel plate shape, the amount of heat conduction and the amount of heat radiation from the heater 14b are large, so that the same effect as the first embodiment is obtained. .

[0015]

[Third Embodiment] FIG. 3 is a perspective view of a central heater auxiliary support portion showing a third embodiment of the present invention.

This embodiment is the same as the first embodiment except that it comprises a heater auxiliary support 25b using two heater auxiliary supports of the first embodiment and has a structure in which the heater 24b is sandwiched. Therefore, the same reference numerals are given to the same portions, and the description thereof will be omitted.

In this embodiment, since the heater 24b is sandwiched between two central heater auxiliary supports 25b, the amount of heat conduction from the heater 24b is large, and the same effect as the first embodiment is obtained.

[0018]

As described above, according to the present invention, the area of the central heater auxiliary support of the cathode assembly of the color picture tube is increased to increase the volume, or the heater auxiliary support is formed into a corrugated plate. To do. Alternatively, by using two sheets, all three cathodes for blue, green, and red can obtain stable and stable electron emission characteristics for a long period of time, and highly reliable and high quality that does not cause a change in color tone called white balance breakdown. It is possible to obtain a color picture tube.

[Brief description of drawings]

FIG. 1 is a sectional view of a cathode structure of a color picture tube showing an embodiment of the present invention.

FIG. 2 is a perspective view of a heater auxiliary support portion in the center of the cathode assembly according to the second embodiment.

FIG. 3 is a perspective view of a heater auxiliary support portion in the center of the cathode assembly according to the third embodiment.

FIG. 4 is a sectional view showing an example of a cathode assembly of a conventional color picture tube.

[Explanation of symbols]

 1a, 1b, 1c cathode sleeve 2a, 2b, 2c base metal 3a, 3b, 3c alkaline earth metal oxide 4a, 4b, 4c, 14b, 24b heater 5a, 5b, 5c, 15b, 25b heater auxiliary support 6a, 6b, 6c heater support 7a, 7b, 7c heater connection

Claims (4)

[Claims] 1. A blue base metal comprising a reducing agent, which is shaped like a cap, is fixed on the upper portion of the cathode sleeve, an alkaline earth metal oxide is coated on the base metal, and a heater is inserted inside the cathode sleeve. In the cathode assembly of the color picture tube, the three cathodes for green and red are supported by the respective heater auxiliary supports and the heater supports and fixed in a straight line.
A cathode assembly of a color picture tube, wherein the heater auxiliary support located at the center of the individual cathodes has a larger volume than the heater auxiliary supports located on both sides. 2. The cathode assembly of a color picture tube according to claim 1, wherein the heater auxiliary support located at the center is made larger in area or made thicker to have a larger volume. 3. The cathode assembly of a color picture tube according to claim 1, wherein the heater auxiliary support located at the center is formed in a wave shape. 4. A heater auxiliary support located at the center is
2. The sheet is used and sandwiched between the heaters.
The cathode assembly of the described color picture tube.