JPH07235272A - Cathode structure of color cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent white balance from being lost during a long period of use, in the in-line type cathode-ray tube of a color cathode-ray tube. CONSTITUTION:Contact parts are minimized by providing dot-like projections 20a, 20b, and 20c partially at the respective cathode supporters 12a, 12b, and 12c to be welded with each sleeve 2a, 2b, and 2c, and the heating value that each heater 5a, 5b, and 5c receives is not let go and the temperatures from the cathode sleeves 2a, 2b, and 2c to cathode supporters 3a, 3b, and 3c are kept balanced, and the evaporation speed of a reducing agent is equalized. Hereby, a highly reliable cathode structure for a cathode-ray tube, where the change of color tone such as the crumbling of white balance during a long period of use, etc., does not occur, can be 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 inline type cathode assembly.

[0002]

2. Description of the Related Art An in-line type cathode structure is constructed by welding a cathode sleeve to three cathode supports which are arranged and fixed in a straight line and inserting a heater therein. Conventionally,
In this type of cathode support, the contact portion with the cathode sleeve was planar and spread over a wide area.

FIG. 2 is a sectional view of an example of a cathode assembly of a conventional color cathode ray tube.

Conventionally, this type of cathode assembly has contacted portions 10a, 1 with respective cathode supports 9a, 9b, 9c as shown in the figure.
Two or more welding points 11 each of 0b and 10c
cathode sleeves 2a, 2 fixed by a, 11b, 11c
heaters 5a, 5b, 5 inserted from the open ends of b, 2c
cap-shaped cathode base metal 3a, which is heated by c and welded and fixed to the tops of the cathode sleeves 2a, 2b, 2c,
The reaction between the reducing agent contained in 3b, 3c and the alkaline earth metal oxides 4a, 4b, 4c applied to the reducing agent is promoted, and the cathode base metal 3a, 3b, 3c is heated to 700 to 800 ° C.
The electron emission was carried out by heating to the operating temperature of.

[0005]

In the above-mentioned conventional cathode assembly, the contact portion between the cathode supports 12a, 12b, 12c and the cathode sleeves 2a, 2b, 2c is planar and has a wide area, so that the amount of heat conduction is unsatisfactory. It is stable, and therefore the temperature balance of the three cathode base metals 3a, 3b, 3c is disturbed, and the evaporation rate of the reducing agents such as Mg and Si contained in the higher temperature cathode base metals 3a, 3b, 3c is accelerated. The electron emission characteristics of the higher temperature cathode begin to deteriorate earlier than the electron emission characteristics of the lower temperature cathode during long-term use,
There was a drawback such as a change in color tone called white balance collapse.

An object of the present invention is to obtain a highly reliable cathode assembly of a color cathode ray tube in which the temperature of the cathode base metal of the cathodes of the three cathodes is kept constant and a change in color tone called white balance collapse does not occur. Especially.

[0007]

In the cathode assembly of the color cathode ray tube according to the present invention, a cap-shaped cathode base metal containing a reducing agent is welded to the upper part of the cathode sleeve, and an alkaline earth metal oxide is formed thereon. In the cathode assembly of a color cathode ray tube, in which three cathodes for blue, green, and red, which are covered with, and in which a heater is inserted inside the cathode sleeve, are supported by respective cathode supports and arranged and fixed in a straight line, It is characterized in that the cathode support is provided with means for stabilizing the amount of heat conduction, which is composed of point-shaped or band-shaped convex portions, and the contact portion with the cathode sleeve is minimized to the minimum necessary.

[0008]

According to the above construction, it is possible to keep the heat balance from the three cathode sleeves to the respective cathode supports and keep the temperature balance of the three cathode base metals. It is possible to obtain a highly reliable cathode assembly of a color cathode ray tube in which the unbalance of the deterioration of the electron emission characteristics of (1) is eliminated, and the change in color tone called white balance collapse does not occur during long-term use.

[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 of a color cathode ray tube which is an embodiment of the present invention.

As shown in FIG. 1, the cathode assembly according to the present invention has 3
The individual cathodes 1a, 1b, 1c are arranged in a straight line in parallel and supported and fixed to a glass rod (not shown) via cathode supports 12a, 12b, 12c. Each cathode 1a, 1b, 1c
Are cathode sleeves 2a, 2b, 2c, cathode base metals 3a, 3b, 3c fixed by welding to them, and alkaline earth metal oxides 4a, 4b applied on top of the cathode base metals 3a, 3b, 3c. 4c, heaters 5a, 5b, 5c are inserted in the respective cathode sleeves 2a, 2b, 2c, heater auxiliary supports 6a, 6b, 6c, heater supports 7a, 17b, 7c, heater connection body. 8a, 8b,
It is welded and fixed to 8c.

Further, each cathode 12a, 12b, 12
Each of c is a dot-shaped convex portion 2 which is a means for stabilizing the amount of heat conduction.
0a, 20b, 20c are provided, and the cathode sleeve 2
a), 2b, 2c, the contact portions with a minimum, the cathode sleeves 2a, 2b, 2c to the cathode support 12a, 1c.
2, heat transfer to b12c, welding points 11a, 11b, 11
It is stable only from c.

According to this embodiment, the heaters 5a, 5b, 5
The conduction of heat received from c is balanced in the three cathodes 1a, 1b, 1c, and the cathode base metal 3
Since a, 3b, and 3c can be set to the same temperature, a uniform reducing agent evaporation rate can be obtained, and a well-balanced cathode assembly of the color cathode ray tube can be obtained.

In the above embodiment, the dot-shaped convex portion is used as an example of the means for stabilizing heat conduction provided on the cathode support, but a belt-shaped convex portion may be used.

[0015]

As described above, according to the present invention, in the in-line type cathode assembly of the color cathode ray tube, since the means for stabilizing the amount of heat conduction is provided in the cathode support, the amount of heat received by the cathode from the heater is transferred from the cathode sleeve. Conducting stable conduction to the cathode support, making the temperature of the three cathode base metals the same, and equalizing the evaporation rate of the reducing agent for a long period of time. There is an effect that a cathode structure for a high color cathode ray tube can be obtained.

[Brief description of drawings]

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

FIG. 2 is a sectional view of an example of a cathode assembly of a conventional color cathode ray tube.

[Explanation of symbols]

 1a, 1b, 1c cathode 2a, 2b, 2c cathode sleeve 3a, 3b, 3c cathode base metal 4a, 4b, 4c alkaline earth metal oxide 5a, 5b, 5c heater 6a, 6b, 6c heater auxiliary support 7a, 7b , 7c Heater support 8a, 8b, 8c Heater connecting body 12a, 12b, 12c Cathode support 20a, 20b, 20c Convex part (dot or strip)

Claims (3)

[Claims] 1. A blue base metal, which is shaped like a cap and contains a reducing agent, is welded to the upper portion of the cathode sleeve, the alkaline earth metal oxide is coated on the cathode base metal, and a heater is inserted inside the cathode sleeve. In a cathode assembly of a color cathode ray tube in which three cathodes for green, red, and red are supported by respective cathode supports and arranged and fixed in a straight line, heat conduction from the three cathode sleeves to the respective cathode supports. A cathode assembly for a color cathode ray tube, comprising a means for stabilizing the amount of heat conduction provided on a cathode support for keeping the amount constant. 2. The cathode assembly of a color cathode ray tube according to claim 1, wherein the means for stabilizing the amount of heat conduction provided on the cathode support is a point-like convex portion. 3. The cathode assembly of a color cathode battleship according to claim 1, wherein the means for stabilizing the amount of heat conduction provided on the cathode support is a strip-shaped convex portion.