JPH0538751U - Cathode structure - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a cathode assembly for an electron gun, which has a small amount of variation in the amount of carbonate adhering, a small variation in characteristics, a good heater heating efficiency, and a long heater life. [Structure] The protrusion 1 is provided on the bottom of the metal tubular portion 1 on the heater 4 side.
By forming a, and by adhering the carbonate 3 to the surface including the concave portion 1b on the opposite side of the protruding portion 1a, the carbonate is made thick at the central portion and thin at the peripheral portion. [Effect] Since the amount of carbonate adhering to the peripheral portion can be reduced without reducing the amount of carbonate adhering to the central portion of the bottom that is effective for electron emission, the heater heating efficiency is improved and the heater life is extended. Further, since it is possible to reduce the fluctuation of the amount of carbonate adhering to the central portion, it is possible to suppress the fluctuation of the characteristics, and it is possible to provide an electron gun with improved reliability and characteristics.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electron gun for a cathode ray tube, and particularly to a structure of a cathode structure.

[0002]

[Prior Art]

 As shown in FIG. 2, a cathode assembly of an electron gun for a cathode ray tube has conventionally been formed by welding a metal tubular portion 1 having a flat bottom to one opening of an inner tubular portion 2 having openings at both ends. Then, a carbonate 3 as an electron emitting substance is attached to the outside of the flat bottom of the metal tubular portion 1 by spraying or the like, and a heater 4 is inserted into the inner tubular portion 2.

[0003]

[Problems to be solved by the device]

 By the way, in the above-mentioned conventional cathode assembly, since the bottom portion of the metal tubular portion 1 is flat, the carbonate 3 is attached to the central portion and the peripheral portion in a uniform thickness, and mainly emits electrons. There was a drawback in that the thickness of the carbonate in the central part was directly affected by the change in the amount of adhesion and fluctuated, and the characteristics fluctuated.

Further, since the heating efficiency of the heater is not sufficient, it is difficult to lower the heater temperature and there is a problem in terms of life.

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention is directed to a cathode structure in which an electron emitting substance is attached to the outer surface of the bottom of a metal tubular part, and the thickness of the electron emitting substance is increased in the central part and in the peripheral part. It is characterized by being attached thinly.

Further, the present invention is characterized in that a concave portion is provided in a central portion of an outer surface of a bottom portion of the metal tubular portion.

Further, in the cathode assembly in which the electron emitting substance is adhered to the metal tubular portion having the bottom portion, the projection portion projecting to the heater side of the bottom portion of the metal tubular portion is formed. Is.

[0008]

[Action]

 According to the above configuration, the thickness of the carbonate in the central portion is larger than that in the peripheral portion, so that the amount of carbonate attached in the central portion can be reduced without decreasing the amount of carbonate attached in the central portion effective for electron emission. As a result, the heater heating efficiency can be improved and the heater life can be extended.

Further, since the variation in the amount of carbonate adhering to the central portion can be made relatively smaller than that in the peripheral portion, the variation in characteristics can be suppressed. Further, since the protrusion is formed on the heater side of the bottom, the distance from the heater is reduced, the heating efficiency of the heater is improved, and the life can be extended in synergy with the increase in the amount of carbonate adhering.

[0010]

【Example】

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

FIG. 1 is a sectional view of a cathode assembly according to an embodiment of the present invention. In the figure, 1 is a metal tubular portion, 1a is a protrusion formed on the heater side, 1b is a concave portion formed on the carbonate side, 2 is an inner tubular portion, 3 is a carbonate as an electron emitting substance, 4 Is a heater.

According to the above configuration, since the concave portion 1b is formed in the central portion of the bottom of the metal tubular portion 1 on the side where the carbonate 3 is attached, the central portion of the carbonate 3 is more than the peripheral portion. Is thicker. Therefore, the amount of carbonate 3 adhered per unit area is larger in the central area than in the peripheral area. Even if the bottom is not flat and has the concave portion 1b, the liquid level becomes almost constant due to direct fluidization of the carbonate solution deposited by spraying or the like, so the total amount of deposition fluctuates and the liquid level changes. Even if it goes up and down, the rate of change in the amount of adhesion in the central part is relatively smaller than that in the peripheral part because the thickness is different. As a result, it is possible to suppress fluctuations in the amount of the attached hydrochloride 3 in the central portion effective for electron emission, and thus to suppress fluctuations in the characteristics of the electron gun to a minimum.

Further, with the above configuration, the effective total amount of the carbonate 3 deposited in the central portion can be reduced, so that the heating efficiency of the heater 4 can be improved, and the heater temperature can be reduced accordingly. Thus, the life of the heater 4 can be extended.

Furthermore, since the protrusion 1a is formed on the heater side at the bottom, the distance from the heater 4 is reduced, and the heating efficiency of the heater 4 is improved.

As described above, according to the present invention, it is possible to realize a high-quality and long-life electron gun by combining the above-mentioned effects.

In the above embodiment, the structure in which the inwardly projecting portion 1a is formed on the inner side surface of the bottom of the metal tubular portion 1 and the concave portion 1b is formed on the outer side surface has been described. Such a structure can be easily obtained by simultaneously forming the protrusions 1a and the recesses 1b during the press molding of the metal tubular portion 1, and moreover, by easily attaching the carbonate 3 by a spray method or the like, the carbonate can be easily formed. The salt 3 can be thickly attached to the central portion and thinly attached to the peripheral portion.

However, the present invention is not limited to such a structure, and the bottom of the metal tubular portion 1 remains flat, and the carbonate 3 may be attached thick in the central portion and thin in the peripheral portion. However, only the concave portion 1b may be provided on the outer surface of the bottom of the metal tubular portion 1.

[0018]

[Effect of the device]

 As described above, the present invention can increase the amount of carbonate adhering to the central portion effective for electron emission and change it by varying the thickness of the electron-emitting substance in the central portion and thinly in the peripheral portion. In addition to reducing the size of the metal tubular part, by forming a recess in the center of the outer surface of the bottom of the metal tubular part, it is possible to easily form a thick electron-emissive material in the central part and thinly in the peripheral part. By forming the protrusion protruding toward the heater on the bottom of the cylindrical portion, the heating efficiency of the heater can be improved, and there is an effect that a high quality and long-life electron electrode assembly can be provided.

[Brief description of drawings]

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

FIG. 2 is a sectional view of a conventional cathode assembly.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal tubular part 1a Projection part 1b Recessed part 2 Inner tubular part 3 Carbonate 4 Heater

Claims (3)

[Scope of utility model registration request] 1. A cathode structure in which an electron emitting substance is attached to the outer surface of the bottom of a metal tubular part, wherein the thickness of the electron emitting substance is thick in the central portion and thin in the peripheral portion. Structure. 2. The cathode assembly according to claim 1, wherein a recess is provided in a central portion of an outer surface of a bottom portion of the metal tubular portion. 3. A cathode assembly having an electron emitting substance adhered to the outer surface of the bottom of a metal tubular portion having a bottom, wherein an inward projection is formed at the bottom of the metal tubular portion. Cathode structure.