JPH06162959A - Electron gun for color cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent the deformation of a cylindrical electrode in supporting the electrode in insulated state on a vitreous rod via a bracket. CONSTITUTION:A final accelerating electrode 13 is formed out of a cylindrical body 14 of elliptical cross section having two opposite flat sections 14a and 14b and other two opposite curved sections 14c and 14d, and an electric field correcting division 15 laid therein. The cylindrical body 14 is supported in insulated state on vitreous rods 6 and 7 by means of metal brackets 16a and 16b. Furthermore, the welded points of the brackets 16a and 16b with the external surface of the cylindrical body 14 are set in the vicinity of a boundary between the flat sections 14a and 14b, and curved sections 14c and 14d. As a result, the cylindrical body 14, even when subjected to a strong pressing force through the brackets 16a and 16b, becomes free from deformation. Thus, the electrode 13 can be supported on the rods 6 and 7 in insulated stated at high yield without any need of using a complicated jig.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun incorporated in a color picture tube to generate an electron beam, and more particularly to an in-line type electron gun.

[0002]

2. Description of the Related Art Generally, an in-line type electron gun is constructed as shown in FIG. That is, three cathodes 1, control grid electrodes 2, which are arranged inline in a direction perpendicular to the plane of the drawing,
An accelerating electrode 3, a focusing electrode 4 and a final accelerating electrode 5,
These electrodes are insulated and supported by a pair of glass rods 6 and 7 provided on both sides thereof. 8 is the top unit,
Reference numeral 9 indicates a metal spring for power supply.

An electrode support structure in which the tip of a tab integrally formed with the end of the electrode is embedded in the glass rod, and an electrode support in which the tip of a metal bracket having the base end welded to the outer surface of the electrode is embedded in the glass rod. There is a structure, and these are used properly according to the shape of the electrode and the like. In the illustrated electron gun, the former is applied to the support structure of the acceleration electrode 3 and the focusing electrode 4, and the latter is applied to the support structure of the control grid electrode 2 and the final acceleration electrode 5.

The final accelerating electrode 5, together with the focusing electrode 4, produces a main lens electric field. It is advantageous in terms of spherical aberration that the diameter of the main lens electric field is as large as possible. In the electron gun disclosed in Japanese Unexamined Patent Publication (Kokai) No. 4-133247 and the like, a cylindrical body having an elliptical cross section is used for the focusing electrode and the final accelerating electrode, and three electron beam passage holes are arranged inline to correct an electric field A partition plate is provided in the cylindrical body.
By using the electrodes thus configured, it is possible to generate three large aperture main lens electric fields, so that an electron gun particularly suitable for a high definition color picture tube can be obtained.
FIG. 4 shows an example of such an electrode structure.
Has a partition plate 12 for electric field correction in a tubular body 11 having an oval cross section, and the partition plate 12 has three electron beam passage holes 12a, 12b, 12c arranged in-line. The final accelerating electrode 13 has a partition plate 15 for electric field correction in a tubular body 14 having an oval cross section, and the partition plate 15 has three electron beam passage holes 15a, 15b, 15 arranged inline.
have c.

[0005]

By the way, when the base end of the metal bracket is welded to the outer surface of the electron gun electrode and the tip of the bracket is fixed to the glass rod, the rod is heated to a high temperature. Since the tip of the bracket is pushed into the softened portion, it is easy to deform the electron gun electrode during this step. In particular, since a slight deformation is not allowed in the electrode structure as shown in FIG. 4, various techniques and complicated jigs are required for insulating and supporting the electrodes.

[0006]

According to the present invention, a final accelerating electrode for generating a main lens electric field together with a focusing electrode has an oval cross section having two flat surface portions facing each other and two curved surface portions facing each other. And a field-correcting partition plate provided therein, the partition plate having three electron beam passage holes arranged inline, and the cylindrical body having a metal bracket interposed therebetween. In the electron gun insulated and supported by the glass rod, the welding point of the bracket to the outer surface of the cylindrical body is set near the boundary between the flat surface portion and the curved surface portion.

[0007]

With this structure, the cylindrical body forming the final accelerating electrode is insulated and supported by the glass rod running along the flat surface portion (long side) of the cylindrical body. The welding points of the bracket are on both sides of the flat surface portion, that is, near the curved surface portion which is the short side. Therefore, even if a strong pressing force acts on the tubular body through the bracket during the step of embedding both ends of the bracket in the rod, the tubular body is not deformed. Therefore, the final accelerating electrode can be insulated and supported on the vitreous rod with good yield without using a complicated jig.

[0008]

The present invention will be described below with reference to the illustrated embodiments. The final accelerating electrode 13 shown in FIG. 1 and FIG.
A cylindrical body 1 which is substantially similar to that shown in FIG. 1 and has two flat surface portions 14a, 14b facing each other and two curved surface portions 14c, 14d facing each other and having an oval cross section.
4 and a partition plate 15 for correcting an electric field provided therein. The partition plate 15 is arranged inline 3
Has electron beam passage holes 15a, 15b, 15c,
Together with a focusing electrode (not shown) adjacent to this electrode, it produces three large aperture main lens electric fields.

The final accelerating electrode 13 is insulated from the final accelerating electrode 13 by embedding the respective tip portions of the two metal brackets 16a and 16b whose base ends are welded to the outer surface of the tubular body 14 into the respective glass rods 6 and 7. The two brackets 16a, 16b are supported on the outer surface of the tubular body 14.
Each welding point (indicated by X in the figure) of the flat surface portion 14
It is set near the boundary between a and 14b and the curved surface portions 14c and 14d (shown by dotted lines A and B in the figure).

Brackets 16a, 1 for the tubular body 14
Since the welding points of 6b are on both sides of the flat surface portions 14a, 14b, that is, near the curved surface portions 14c, 14d that are the short sides, the respective tip portions of the brackets 16a, 16b are embedded in the rods 7, 8. Even if a strong pressing force acts on the tubular body 14 through the brackets 16a and 16b during the process, the tubular body 14 is not deformed.

The brackets 16a and 16b are not limited to the illustrated shapes. Further, when the number of welding points of the brackets 16a and 16b with respect to the tubular body 14 is large, the initial purpose can be achieved if some of them are set in the vicinity of the boundary A.

[0012]

As described above, according to the present invention, even if a strong pressing force acts on the tubular body through the bracket, the tubular body will not be deformed, so that a final jig can be performed without using a complicated jig. The accelerating electrode can be supported on the glass rod in good yield with good insulation.

[Brief description of drawings]

FIG. 1 is a front view of a main part of an electron gun embodying the present invention.

FIG. 2 is a perspective view of the same main part.

FIG. 3 is a partially cutaway side view of a conventional electron gun.

FIG. 4 is a partially cutaway side view of a conventional electron gun.

[Explanation of symbols]

 6,7 Glass rod 13 Final accelerating electrode 14 Cylindrical body 15 Electric field correction partition plate 16a, 16b Bracket

Claims (1)

[Claims] 1. A final accelerating electrode for generating a main lens electric field together with a focusing electrode has a tubular body having an oval cross section having two flat surface portions facing each other and two curved surface portions facing each other. An electric field correction partition plate provided, the partition plate having three electron beam passage holes arranged in-line, and the cylindrical body being insulated and supported by a glass rod through a metal bracket. In the electron gun, the welding point of the bracket to the outer surface of the cylindrical body is set near the boundary between the flat surface portion and the curved surface portion.