JPS5991636A - Electron gun - Google Patents

Abstract

PURPOSE:To obtain a stable electron emission characteristic while maintaining a fixed interval through the simple constitution by making an elastic body to lie between an insulating base body and a retainer in the cathode structure. CONSTITUTION:A spacer S is interposed into the first grid G followed by housing the cathode structure C in the first grid G so that the insulating base body K3 may make close contact with the spacer S. Thereafter, an elastic body SP such as a spring or the like is interposed into the first grid G, then finally the retainer R presses the cathode structure C through the spring SP while said retainer R is fixed to the first grid G by welding or the like thus making the first grid G to hold the cathode structure C. Thereby, the dimensional scatter in constitution due to external vibration, thermal distortion and thermal expansion can be dissolved thus being able to properly maintain an interval between cathode and the first grid and to obtain a stable radiation current.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron gun used in a cathode ray tube or the like.

The configuration of a conventional electron gun of this type is shown in FIG. In the figure, G is a first grid consisting of a cylinder with a bottom, and this first grid G includes a spacer S1, a cathode structure o (K, m
1:4g) and retainer R are charged, and by welding retainer R to the first grid,
The cathode assembly 0 is fixed to the first grid G. Here, the cathode assembly 0 is one in which a cathode, a fillet Kt, and an insulating base 3 are integrally fixed by welding. Note that H is a heater.

By the way, what is important in assembling such an electron gun is to keep the distance α between the bottom of the first grid G and the cathode X as constant as possible with high precision. However, in reality, the pressure bonding strength of the retainer R, the inclination of the spacer S and the cathode area,
Due to thermal strain during operation, external vibrations, and the difference in thermal expansion between the first grid G, the spacer 8-retainer a, and the insulating base 3, etc., the above-mentioned interval α becomes constant.
, which causes a change in the radiation current during actual operation.7 This leads to a change in the brightness of the cathode ray tube, and in a color tube, it causes deterioration in information transmission due to chromaticity difference.

The present invention has been made in order to eliminate these drawbacks, and an object of the present invention is to provide an electron gun that can maintain the above-mentioned interval constant and obtain stable electron emission characteristics with a simple configuration. It is an object.

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

FIG. 2 is a sectional view showing an example of an electron gun according to the present invention, and the same parts as in FIG. In the figure, 8P is an elastic body, such as a spring, and is interposed between 1 and 3--R on the insulating base.

This electron gun is assembled as follows.
First grid Gk: - A spacer S is inserted, and then the cathode assembly 0 is housed in the first grid G in such a way that the insulating substrate 3 is in contact with the spacer S. After that, the spring SP is inserted into the first grid G, and finally, the retainer R is used to press the cathode assembly C via the spring 8F, and the retainer R is fixed to the first grid G by welding or the like. As a result, the cathode assembly 0 is held on the first grid G.

With this configuration, even if the spacing d tends to fluctuate due to the aforementioned thermal strain, vibration, etc., it can be absorbed by the spring 8P, and therefore the spacing d can be stably maintained.

By the way, in terms of stability during operation, if a shape memory metal is used for the spring sp and the spacer 8 and the insulating base section 3 are pressed together when the temperature rises, the retainer R can be properly welded, etc. A more stable spacing d can be obtained simply by fixing at , which greatly improves work efficiency.

Note that the above-mentioned elastic body is not limited to the spring sp, but can be appropriately selected from other elastic materials.

In addition, although the above embodiment described a single cathode,
The above configuration can be similarly applied to the cathode of a color tube having multiple beams.

As described above, according to the present invention, by interposing an elastic body between the insulating base and the retainer in the cathode structure, variations in assembly dimensions caused by external vibration, thermal strain, thermal expansion, etc. are eliminated. Therefore, the distance between the cathode and the first grid can be maintained appropriately, and a constant V radiation current can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional electron gun, and FIG. 2 is a sectional view showing an example of an electron gun according to the present invention. 0... Cathode structure, G... First grid, K... Cathode, K2... Eyelet % K) 1... Edge base,
R... property → -1, S... spacer, sp...
Elastic body, d... spacing. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno (1 other person) Figure 1 and Figure 2

Claims (1)

[Claims] fl), a first grid consisting of a cylindrical body with a bottom, a cathode assembly having a cathode eyelet and an insulating base holding the cathode and the eyelet, and housed in the first grid; and a cathode assembly housed in the first grid. a spacer inserted into the first grid to maintain a distance between the bottomed part of the first grid and the corresponding cathode; and a spacer fixed to the first grid at a position where the insulating base of the cathode structure is sandwiched between the spacer and the cathode. An electron gun comprising: a retainer for holding the structure on the first grid; and an elastic body interposed between the insulating base and the retainer.