JPS5944746A - Manufacture of heater structure for electron tube - Google Patents

Abstract

PURPOSE:To enhance welding strength and yield rate by irradiating the tab with laser beam from the side opposing to the surface of heater tab to which the end point of heater leg portion to be inserted into the cathode sleeve and by heating the end point thereof up to a specified temperature for welding. CONSTITUTION:A heater 10 is inserted into the cathode sleeve secured to the top surface of base metal plate to which electron radioactive substance is deposited and it is supported through a heater tab 11. The heater end 10C is disposed to the specified position on the surface of tab 11 and it is irradiated with the laser beam from the rear side thereof. Simultaneously, such area is heated up to 400-600 deg.C by supplying the power to the end 10C. Thereby, the end 10C and tab 11 are welded and secured. Accordingly, fused metal 11A can be wound well and welding strength can also be enhanced. Moreover working efficiency and manufacturing yield rate can also be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a heater assembly disposed in an electron tube, particularly a heater assembly suitable for use as a cathode for a negative (evening tube). An example of a cathode used in an electron tube, such as a cathode 41! tube, is shown in Fig. 1.The first grid (1) is held by the first grid holding strap (2). The cathode body (3) provided opposite to the cathode sleeve (4) and the base metal plate (5) facing the first grid on the top thereof and coated with an electron emitting substance on the surface 1, This cathode sleeve (4) is supported by a cathode support tube (7) via cathode supports (6) attached at 120 degree intervals, and this cathode support tube (7) supports a cathode report (8). It is fixed to the cathode holding strap (9) through the cathode sleeve (
4) is supported by the heater strap (1) through the heater U (ν is the heater tab 01) inserted in the inner They are fixed at a predetermined interval, and this insulating support rod (+3) is connected to the stem 0 by the support.
4) is fixed.

A cathode ray tube equipped with the cathode 41'q body formed in this manner is required to improve the first characteristics such as interlocking performance and energy saving, and therefore it is necessary to reduce the heat capacity of the cathode body. Various countermeasures have been taken, including improving the thermal efficiency of heaters. For example, one way to reduce heat capacity is to reduce the diameter and thickness of the cathode sleeve and metal plate, and one way to improve thermal efficiency is to form a dark green chromium oxide film on the surface of the cathode sleeve. We are working to improve the characteristics of each. The heater inserted into such a cathode sleeve and placed at a predetermined position is fixed by welding to the heater tab. The electron gun is formed by cutting and removing the cut portion Oe of the heater tab.The heater includes a main heating section (10A) in which a heater wire made of a high melting point metal such as tungsten is spirally wound, and a main heating section connected to the main heating section. Generally, the heater wire is extremely thin, and when it is inserted into the cathode sleeve, it may be bent or the insertion degree may be uneven. Failure to do so may cause problems such as fluctuations in the operating temperature of the cathode ray tube, so to prevent such problems from occurring, the heater is welded and fixed to the metal heater tab in advance.

In this way, attach the end of the heater leg (IOc) to the heater tab (
The method of fixing the heater end (hereinafter referred to as the heater end) has been done by resistance welding. When the load on the welding electrode is reduced, welding often becomes unstable, and in any case, quality is degraded.

In order to avoid these problems, there is a method of irradiating the heater tab with laser light and welding and fixing the end of the heater.

In this method, the heater tab material is partially melted, and the molten metal wraps and connects the heater end using surface tension. Depending on the contact between the heater end (10C) and the heater end surface, dirt on the surface of the heater end, etc., the degree to which the molten metal is drawn into the heater end varies, and as shown in FIG. A gap was created between the weld and the surface, which caused a lack of stability in welding quality.

[Purpose of the invention]

The present invention has been made in view of these points, and
When welding and fixing the end of the heater to the heater tab by laser beam irradiation, it is possible to reduce the variation in the molten metal of the heater tab material melted by the laser beam being caught in the heater end, and to achieve good welding fixation. The present invention aims to provide a method for manufacturing a heater structure in which the welding strength is increased, a heater can be inserted into a cathode sleeve through a predetermined hole, and the heater structure can contribute to stabilizing the characteristics of an electron tube in which the cathode is disposed.

[Summary of the invention]

In the method of the present invention, when manufacturing a heater structure for an electron tube, when welding and fixing a heater end to a heater tab, a laser beam is irradiated from the back surface of the heater tab opposite to the front surface of the heater tab to which the heater is fixed, and the heater end is part from 400°
It is a method of welding and fixing by heating to 6000C, and is characterized by eliminating welding flutter and improving welding strength. [Embodiments of the Invention] The following is a pH of one embodiment of the present invention. CjiTA explains. if
, As shown in Figure 3, the surface glue of the heater tab θυ as the connector where the heater 3.1 complete part (river (:) is connected to both ends [
Place the heater end (10C) in a fixed position, and apply a laser beam, for example YA, from the back side of the heater tab as shown by the arrow in the figure.
While irradiating the laser beam from the G oscillator, the heater end (IOC) is heated to about 5 () OoC by being energized, and the heater end is welded and fixed to the Peter tab to form a single heater tie.

When welding in this way, there is no moisture or oil on the surface of the heater end.
Even if dirt is present, these dirts will be removed by heating.In addition, the γi14H claw between the molten metal of the heater tab material and the end of the heater will also be smaller, improving wettability. t+f2 J The amount of molten metal involved in the end of the heater increases, and the variation thereof decreases, so that a good heater groove body with strong welding strength is formed.

Therefore, it can be inserted into the cathode sleeve in a predetermined manner without any inconvenience. FIG. 4 shows a state in which the end of the heater is welded and fixed to the heater tab. θ1) is the heater tab, and (1oC) is the heater end. They are well bonded without any gaps, and the molten metal U+A)′ is well rolled in.

If the heating temperature at the end of the heater is lower than 400° C., water and oil can be removed, but foreign matter such as dust cannot be removed, and the wettability of the heater to the molten metal in the heater tab deteriorates. In addition, if the temperature is higher than 6000C, the heater wire becomes oxidized, and if the temperature rises further, the heater wire becomes brittle. Therefore, the heating temperature at the end of the heater is preferably in the range of 4 (100 to 600°C).

In this way, the heater is welded and fixed to the heater tab, forming a heater structure with strong welding strength, which further improves yield and work efficiency.

〔Effect of the invention〕

When the heater end is welded and fixed to the heater tab by the method of the present invention, a heater structure with good welding strength and improved reliability can be formed, and work efficiency and yield can be improved. .

Although the above explanation has been made regarding the cathode of a cathode ray tube, it is needless to say that it is not limited to this and is also applicable to methods of manufacturing heater structures disposed in other electron tubes. .

[Brief explanation of the drawing]

Figure 1 is a front view showing the cathode structure and its surroundings in one place, Figure 2 is a cross-sectional view of the conventional heater end welded to the heater tab (4); ) ke side view, 3rd
The figure is an explanatory diagram showing a state in which the heater structure of the present invention is formed;
@ Figure 4 shows a part of the heater structure of the present invention, where the lower figure is a cross section and the figure ([3) is a side view. 3... Cathode body 4... Cathode sleeve 5...
Base metal plate 10...Heater 10A...Heater main heating part JOB...Heater leg 10C...Heater end 11...Heater tab representative Patent attorney Inoue -
Male Figure 1 Figure 2 Cause Figure 3 F Figure 4

Claims (1)

[Claims] The main heating section has an insulating layer formed on its surface by winding the heater wire inside the cathode sleeve, which has a base plate coated with an electron radioactive material fixed to the top, and this main heating section. A method for manufacturing an electron tube heater structure in which a heater is inserted and has legs extending continuously from the heater tab, and the ends of the legs of the heater are fixed to heater tabs. A heater structure for a Kaji tube, characterized in that the heater tab is irradiated with a laser beam from the side opposite to the surface of the heater tab to which the heater tab is fixed, and the end portion of the heater is heated to 4000 to 6009 C to weld and fix the heater to the heater tab. Production method.