JPH05251012A - Color picture tube - Google Patents

Abstract

PURPOSE:To prevent the lowering of resolution of a picture tube, in the case of forming electron beam passing holes in both sides, on the acceleration electrode side, of a focusing electrode in oblong shapes in such a convergence structure at allowing electron beam on both sides to swing inward by means of prefocus lens fields on both sides. CONSTITUTION:A center electron beam passing hole 15b formed in the end face 14, facing an accelerating electrode of a focusing electrode 11 is shaped to be long sideways and to be substantially the same electron beam passing holes as 15a, 15c in both side areas of the end face 14, in its shape and sice. In this construction not only that the electrode assembling precision can be raised, but also the vertical diameter of the center electron beam can be made almost the same as those of both side electron beams, and high resolution picture with less color deviation can be made all over a phosphor screen.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-line type color picture tube having a convergence structure in which electron beams on both sides are swung inward by electric fields of prefocus lenses on both sides.

[0002]

2. Description of the Related Art A color picture tube having a convergence structure in which electron beams on both sides are swung inward by electric fields of prefocus lenses on both sides is disclosed in Japanese Patent Publication No. 1-292999. The color picture tube thus constructed has a conventional structure in which the electron beams on both sides are swung inward by the electric field of the main lens on both sides (Japanese Patent Publication No. 52-4905).
3) on the center and both sides
The two main lens electric fields can be made axially symmetrical, and in particular, the assembling accuracy of the electrodes in the main lens electric field generating section can be improved.

Of the three electron beam passage holes on the end face of the focusing electrode on the accelerating electrode side, if the ones on both sides are made horizontally long with the long axis in the horizontal direction, the assembling precision of the electrodes in the prefocus lens electric field generating section is particularly high. Can also be increased. In this case, as shown in FIG.
While the individual electron beam passage holes 2a, 2b, 2c are circular, the electron beam passage holes 5a, 5c on both sides of the accelerating electrode side end surface 4 of the focusing electrode 3 have a horizontally long shape in which the major axis is horizontal. The distance A between the central axes is set to be larger than the distance B between the central axes of the electron beam passage holes 2a and 2c on both sides of the acceleration electrode 1. Therefore, the pair of cylindrical pins 6a, 6b of the electron gun assembly jig can be inserted into the electron beam passage holes 5a, 5c on both sides of the focusing electrode 3 and the electron beam passage holes 2a, 2c on both sides of the acceleration electrode 1. The electrode can be assembled accurately.

[0004]

However, while the electron beam passage holes 2a and 2c on both sides of the accelerating electrode 1 are circular, the electron beam passage holes on both sides of the end face 4 on the accelerating electrode side of the focusing electrode 3 are formed. When 5a and 5c are horizontally long,
The vertical diameter of the electron beam passing through the electric field of the main lens on both sides becomes larger than the vertical diameter of the electron beam passing through the electric field of the main lens of the center, and the beam spot generated especially on the peripheral part of the fluorescent screen becomes large. It becomes large and the resolution is lowered.

[0005]

According to the present invention, in the color picture tube constructed as described above, the center electron beam passage hole provided at the end face of the focusing electrode on the side of the acceleration electrode is provided.
A laterally elongated shape having substantially the same shape and size as the electron beam passage holes on both sides of the same end face is used.

[0006]

With this structure, the beam focusing action by the center prefocus lens electric field becomes similar to the beam focusing action by the prefocus lens electric fields on both sides, and the electron beams on the center and on both sides passing through the three main lenses. The vertical diameters of are aligned. However,
Although the vertical diameters of the three electron beams are larger than the horizontal diameter, this is because, for example, the three electron beam passage holes of the accelerating electrode can be seen on the auxiliary electrode plate that is superposed on the end surface of the accelerating electrode on the focusing electrode side. The problem can be solved by generating a quadrupole electric field by providing three comparatively large vertically elongated through holes. It can also be solved by adjusting the deflection magnetic field distribution.

[0007]

The present invention will be described below with reference to the illustrated embodiments. The in-line type electron gun shown in FIG. 1 has three cathodes 7a, 7b and 7c arranged in a line in the horizontal direction,
The control grid electrode 8, the accelerating electrode 9, and the three prefocus lens electric fields 10a, 10b,
A box-shaped focusing electrode 11 for generating 10c, and main lens electric fields 12a, 12b, 12c together with this focusing electrode 11.
And an anode 13 for generating. As shown in FIG. 2, electron beam passage holes 15a, 15b, 15c on both sides and the center of the acceleration electrode side end surface 14 of the focusing electrode 11 are formed.
Are both oval with their long axes in the horizontal direction, and have substantially the same shape and size as each other. However, the center axis mutual distance A between the electron beam passage holes 15a and 15c on both sides is set to be larger than the center axis mutual distance B between the electron beam passage holes 16a and 16c on both sides of the acceleration electrode 9. In addition, E in the figure shows an electron beam.

Since all of the three electron beam passage holes 15a to 15c provided on the end face of the focusing electrode 11 on the side of the accelerating electrode are laterally long, the prefocus of the center and both sides generated between the focusing electrode 11 and the accelerating electrode. The divergence angle of the electron beam in the lens electric field is almost the same, and the vertical diameter of the electron beam passing through the center main lens electric field is almost the same as each vertical diameter of the electron beam passing through the main lens electric fields on both sides. . Therefore, it is possible to display a high resolution image with little color shift even in the peripheral area of the phosphor screen.

Although the focusing electrode in the above-mentioned embodiment is a single one, the present invention has a two-stage structure or four disclosed in Japanese Patent Publication No. 3-60147 and Japanese Patent Laid-Open No. 3-95835. It can also be applied to a device having a focusing electrode having a step structure.
However, in this case, the electron beam passage hole of the center provided on the end face of the first focusing electrode closest to the accelerating electrode on the acceleration electrode side has substantially the same shape and size as the electron beam passage holes on both sides of the same end face. It has a horizontally long shape. Also, a main lens electric field is generated between the anode and the focusing electrode closest to the anode.

[0010]

As described above, according to the present invention, not only can the electrode assembly precision in the main lens electric field generation unit and the electrode assembly precision in the prefocus lens electric field generation unit be improved, but the vertical diameter of the center electron beam can be increased. If it is almost the same as the vertical diameter of the electron beam on both sides, it can be
It is possible to display a high-resolution image with little color shift on the entire phosphor screen.

[Brief description of drawings]

FIG. 1 is a side sectional view of an electron gun of a color picture tube embodying the present invention.

FIG. 2 is a perspective view of a main part of the electron gun.

FIG. 3 is a perspective view showing a relationship between an electron gun electrode of a conventional color picture tube and an assembly jig.

[Explanation of symbols]

 7a to 7c Cathode 8 Control grid electrode 9 Accelerating electrode 11 Focusing electrode 13 Anode 15a to 15c Electron beam passage hole 16a to 16c Electron beam passage hole

Claims (2)

[Claims] 1. A cathode, a control grid electrode, an accelerating electrode, a box-shaped focusing electrode for generating a prefocus lens electric field together with the accelerating electrode, and three main electrodes together with the focusing electrode. An anode for generating a lens electric field, and electron beam passage holes on both sides of the end face of the focusing electrode on the accelerating electrode side are formed in a horizontally long shape having a major axis in the horizontal direction, and the central axes thereof are spaced from each other by a distance between the accelerating electrodes. In a color picture tube in which the distance between the central axes of the side electron beam passage holes is set to be larger than the center electron beam passage hole provided on the end face of the focusing electrode on the side of the acceleration electrode, the electrons on both sides of the end face are formed. A color picture tube characterized by having a horizontally long shape having substantially the same shape and size as a beam passage hole. 2. A horizontal inline array of three cathodes, a control grid electrode, an accelerating electrode, an initial focusing electrode for generating a prefocus lens electric field together with the accelerating electrode, and a box-shaped final focusing electrode. And an anode for generating a main lens electric field together with the final-stage focusing electrode, and electron beam passage holes on both sides of the end face of the initial-stage focusing electrode on the side of the acceleration electrode are horizontally long with the long axis in the horizontal direction. In a color picture tube in which the center axis mutual spacing is set larger than the center axis mutual spacing of the electron beam passage holes on both sides of the accelerating electrode, the center electron beam passage provided on the accelerating electrode side end surface of the first focusing electrode A color picture tube, characterized in that the hole has a horizontally elongated shape having substantially the same shape and size as the electron beam passage holes on both sides of the same end face.