JPS5838523Y2 - electron gun structure - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an electron gun assembly incorporated into a cathode ray tube.

Generally, an electron gun assembly used in a cathode ray tube is composed of a cathode electrode, a plurality of grid electrodes, and a stem that holds each of these electrodes.

In recent years, an electron gun assembly using a directly heated cathode has been developed, and this invention will be described below by taking as an example an integrated in-line type electron gun assembly using this directly heated cathode.

FIG. 1 shows an example of the structure of a conventional electron gun assembly of this type in which the third grating and above, which are not related to the present invention, are omitted.

In FIG. 1, the plurality of holding straps 2 and the first grid electrode 3 and above, which constitute the electron gun assembly 1, are as follows:
Each of them is fixed to bead glass 4, and a cathode part is fixed inside this first grid electrode 3 via an insulator, and a plurality of heater leads 5 are drawn out from this cathode part.

Further, a plurality of inner leads 7 are fixed to the stem 6, and by connecting each inner lead 7 to the holding strap 2 and the heater lead 5, the stem 6 can be used to hold the body structure 1 and to supply external power. I try to do this.

In the above structure, each inner lead 7 is made of manganese nickel wire with a wire diameter of about 0.7 mmφ, for example, in order to obtain sufficient strength to hold the structure, whereas the heater lead 5 is made of a manganese nickel wire with a wire diameter of about 0.3 mmφ. For example, since Kovar wire is used, the heat balance is poor when welding both leads 5 and 7, resulting in unstable welding strength and lack of reliability, and at the same time, due to thermal shock during welding. However, the dowels 8 at the base of each inner lead 7 had some drawbacks such as cracks.

When resistance welding the heater lead 5 and the inner lead 7, the heater lead 5 has a smaller wire diameter than the inner lead 7, so only the heater lead 5 melts during welding due to its small heat capacity, and the inner lead 7 melts during welding. Since it does not melt, the welded parts of both leads do not melt together, and only the heater lead 5 is melted, so the welded part of the heater lead 5 is prone to cracking, cutting, etc., and the weld strength is reduced. This is because the wire diameter of the inner lead 7 is large, so when resistance welding is performed with the heater lead 5, the impact from the resistance welding electrode is caused by the dowel at the base of the inner lead. 8
This is because the dowel 8 is likely to crack because it is applied to the inner lead 7 using the dowel 8 as a fulcrum.

This invention improves the conventional drawbacks, increases the reliability of welding between the heater lead and the inner lead, and also connects each inner lead to the holding strap in order to prevent the occurrence of cracks. The wire diameter of each inner lead, excluding the supporting lead, is made thinner to approach the wire diameter of the heater lead.

An embodiment of this invention will be described below with reference to FIG.

FIG. 2 shows an embodiment of an electron gun assembly according to this invention.

In this FIG. 2, the same reference numerals as those in FIG. The diameter is smaller than the wire diameter of the support lead 7a and closer to the wire diameter of the heater lead 5.

That is, the wire diameter of each inner lead 7b is set to 0, for example.
．． Assuming that the wire diameter is 5 mmφ, the wire diameter Q of the support lead 7a is 7 mmφ.
The wire diameter Q of the heater lead 5 is 3 mmφ.
By bringing the heater lead 5 and the inner lead 7b closer to each other, the difference in heat capacity between the heater lead 5 and the inner lead 7b becomes smaller, and both leads are welded in a welded state, which eliminates problems such as cracking and cutting, and increases welding strength. Moreover, since it is stable, a highly reliable welded part can be obtained.

Furthermore, by reducing the diameter of the inner lead 7b, the impact on the dowel 8 during welding is reduced, and the thickness of the dowel 8 can be increased by the reduced wire diameter.
There is also an advantage that the strength of the dowel 8 portion is increased and cracks in the dowel portion can be prevented.

Each support lead 7a is also connected to the holding strap 2.
In order to obtain sufficient strength for holding the structure by the stem 6, the wire diameter is kept the same as before.

In the above embodiment, the wire diameter of the support lead 7a is Q, 7 mm.
φ, the wire diameter of the other inner lead 7b is Q, 5mmφ
Although the case described above is not limited to this, it is of course applicable to cathode ray tube electron guns other than integrated in-line electron guns using directly heated cathodes.

As described in detail above, according to this invention, among the inner leads held by the stem, the wire diameter of a plurality of inner leads excluding the support lead is smaller than the wire diameter of each support lead, and each inner lead is Since the diameter of the node is close to that of the heater lead to be welded, it is possible to achieve a good heat balance when welding with the heater lead, resulting in highly reliable welding with stable welding strength, as well as It is possible to prevent the occurrence of cracks in the parts, and the method has the advantage of being simple and easy to implement.

[Brief explanation of the drawing]

Fig. 1 is a front view showing the main parts of an integrated in-line electron gun assembly using a conventional directly heated cathode, and Fig. 2 is a main part of an integrated in-line electron gun assembly to which an embodiment of this invention is applied. FIG. 1... Electron gun structure, 2... Holding strap, 3... First grid electrode, 4...
Bead glass, 5... Heater lead, 6...
...Stem, 7a...Support lead, 7b.
...Inner lead, 8...Dowel.

Claims (1)

[Scope of utility model registration request] In an electron gun assembly comprising at least a cathode electrode, a plurality of grid electrodes, and a stem holding each of these electrodes, a plurality of inner leads held by the stem, excluding a support lead supporting the electrodes, are provided. The wire diameter of the inner lead is smaller than the wire diameter of the support lead,
An electron gun assembly characterized in that the wire diameter is close to that of the heater lead for the cathode.