JPS6255262B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron gun for a color picture tube, particularly an in-line color picture tube.

Generally, the aperture of the main lens of a picture tube electron gun has a large effect on focus characteristics, and in order to obtain good focus characteristics, it is desirable that the aperture be as large as possible. However, in an in-line color picture tube electron gun with three electron beam apertures arranged horizontally in a straight line, the aperture and eccentric distance of the three electron beam apertures must be adjusted to increase the aperture of the three main lenses. If the electron beams are expanded, not only will it be difficult to properly converge the three electron beams to any one point on the phosphor screen surface, but also the main lens forming electrode will be close to the valve neck, resulting in poor high voltage characteristics.

The present invention has been made with the above-mentioned points in mind, and the electron gun for color picture tubes of the present invention will be described below along with embodiments shown in the drawings.

In FIG. 1 showing the electrode configuration of a bipotential electron gun embodying the present invention, K ₁ , K ₂ , and K ₃ are cathodes, G ₁ is a control electrode, G ₂ is an accelerating electrode, G ₃ is a focusing electrode, and G ₄ indicates the anode. On the mutually opposing plate surfaces of the focusing electrode G ₃ and the anode G ₄ , which are the main lens forming electrodes,
Large diameter beam passage holes g ₃₁ , g ₃₂ , g ₃₃ and g ₄₁ , g ₄₂ , g ₄₃ for passing three electron beams are arranged in-line on a horizontal straight line, respectively.
However, the beam passage ports g ₃₁ , g ₃₂ , and g ₃₃ are three independent
Instead of individual circular holes, as shown in Fig. 2, three circular holes overlap and communicate with each other at their adjacent ends to form one peanut-shaped hole, that is, a triple circular hole _g3 . ing. Also, beam passage port g ₄₁ ,
g ₄₂ and g ₄₃ are also not three independent circular holes, but a third hole.
As shown in the figure, three circular holes are formed by overlapping adjacent ends of each other and communicating with each other to form one triple circular hole _g4 .

Both flat edges 12 and 13 of the partition electrode 11, which is a U-shaped metal piece attached to the focusing electrode _G3 , serve as partition plates near the two constrictions of the triple circular hole _G3 . In particular, the triple circular hole g ₃ is divided into three substantially horizontal sections, and three substantially independent beam passage ports g ₃₁ ,
g ₃₂ and g ₃₃ are formed. In addition, a partition electrode 1 consisting of a U-shaped metal piece attached to the anode G ₄
4 serve as partition plates in the vicinity of the two constrictions of the triple circular hole g ₄ , so that the triple circular hole g ₄ is also substantially horizontally separated into 3 Three divided and substantially independent beam passage ports g ₄₁ , g ₄₂ , and g ₄₃ are formed. In addition,
The x marks in the figure indicate welding points.

Short cylindrical collar portions 17 and 18 protruding toward the inside of the electrode are formed at the periphery of each of the triple circular holes g ₃ and g ₄ by cutting and raising, respectively, and the diameter is 0.7 mm to 3 mm.
The mutual distance L ₂ between the partition electrode 11 (or 14) having a width L ₁ of about mm and the collar portion 17 (or 18) is set to about 0.5 mm to 2 mm. Furthermore, as shown in FIG. 4, the vertical diameter D' of the beam passage aperture g ₃₂ (or g ₄₂ ) located at the center is the same as that of the beam passage apertures g ₃₁ , g ₃₃ (or g ₄₁ ,
g ₄₃ ) is set slightly larger than the vertical diameter D, and when the eccentric distance S is 5.5 mm and D is 7.0 mm, D' can be set to 7.0 mm <D' ≤ 9.5 mm. . Furthermore, when the inner diameter at the constriction of the triple circular hole is G, the following relational expressions generally hold true: S<D≦1.4S, 0.3S≦G≦0.95S.

Now, D'=D and the partition electrodes 11 and 14
Considering the case where the beam passage holes g ₃₂ and g ₄₂ located in the center are not provided, the horizontal lens action of the central main lens formed near the beam passage holes g ₃₂ and g ₄₂ located in the center will be Passage port g ₃₃ , g ₄₃
This is weaker than the horizontal lens action of the main lenses on both sides formed nearby. The vertical lens action is approximately equal regardless of whether it is in the center or on both sides.

Therefore, the three circular holes g ₃ and g ₄ are partitioned into electrodes 11,
When the partition electrodes 11 and 14 are substantially divided into three sections in the horizontal direction, if the width L ₁ and the mutual distance L ₂ of the partition electrodes 11 and 14 are selected to appropriate values, the horizontal lens action of the main lenses on both sides can be enhanced, It is possible to obtain principal lenses on both sides that are nearly axially symmetrical. However, with regard to the central main lens formed by the central part of the triple circular hole, due to the peculiarity of the hole shape, even if the partition electrodes 11 and 14 are provided, the horizontal lens action becomes the vertical lens action. It is weaker than that, and it is not possible to obtain axially symmetrical characteristics.

Therefore, in the present invention, for example, as described above, the beam passage aperture g ₃₂ (or
g ₄₂ ) is set larger than the vertical diameter D of the beam passage holes g ₃₁ , g ₃₃ (or g ₄₁ , g ₄₃ ) located on both sides. In this case, the vertical lens effect of the central main lens is selectively weakened and approximates the strength of the horizontal lens effect of the central main lens, resulting in good axial symmetry.

Another embodiment of the invention is shown in FIG. In this case, while D=D', the U-shaped partition electrode 11
On each inner surface of both end edges 12 and 13, this both end edge 1
Electric field adjustment metal pieces 18 and 19 with the same width as 2 and 13
are attached to each. Therefore, the substantial horizontal diameter of the central beam passage aperture g ₃₂ formed by the central region of the triple circular hole g ₃ becomes narrower, and the horizontal lens action of the central main lens is selectively strengthened. , the lens has good axial symmetry.
Although only the partition electrode 11 has been described here, it goes without saying that a metal piece for electric field adjustment similar to that described above may be added to the partition electrode 14 as well. Further, these electric field adjusting metal pieces 18 and 19 may be formed of square-shaped metal pieces, an example of which is shown in FIG. In these cases, when S = 5.5 mm and D = 7.0 mm, L ₁ = 0.7 mm to 3 mm, L ₂ = 0.5 mm to 2 mm,
The distance d between the metal pieces 18 and 19 can be set to 2.5 mm to 4.5 mm.

As described above, in the color picture tube electron gun of the present invention, the vertical diameter of the beam passage aperture located at the center is made larger than the vertical diameter of the beam passage apertures located on both sides, or the substantial diameter of the partition electrode is By deviating the partition surface from the constriction of the triple circular hole toward the tube axis side, the vertical diameter/horizontal diameter of the beam passage opening located at the center can be adjusted to the vertical diameter of the beam passage opening located on both sides. The diameter is larger than the diameter in the direction/diameter in the horizontal direction, and the three beam passage holes arranged in-line in the main lens forming electrode can be made large in diameter without increasing the eccentric distance. A color picture tube with excellent convergence characteristics and high voltage characteristics can be provided at low cost. It goes without saying that the present invention is applicable not only to bipotential electron guns but also to unipotential or other types of electron guns.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing the electrode configuration of a bipotential electron gun embodying the present invention, FIGS. 2 and 3 are perspective views of the main parts of the electron gun, and FIG. 4 is a plan view of the main parts. 5 and 6 are plan views of main parts of other embodiments of the present invention. G ₃ ... Focusing electrode, G ₄ ... Anode, g ₃ , g ₄ ... 3
Continuous circular hole, g ₃₁ , g ₃₂ , g ₃₃ , g ₄₁ , g ₄₂ , g ₄₃ ... Beam passage port, 11, 14 ... Partition electrode, 18, 1
9...Metal piece for electric field adjustment.

Claims (1)

[Claims] 1. 3 arranged in-line with the main lens forming electrode.
A beam passage aperture is formed by a triple circular hole and a partition electrode that substantially horizontally divides the triple circular hole into three, and the beam passage aperture located at the center has a vertical diameter/horizontal An electron gun for a color picture tube, characterized in that the diameter in the direction is larger than the vertical diameter/horizontal diameter of the beam passage openings located on both sides. 2. Claim 1, characterized in that the vertical diameter of the beam passage aperture located at the center is larger than the vertical diameter of the beam passage apertures located on both sides.
An electron gun for color picture tubes as described in . 3. The electron gun for a color picture tube according to claim 1, wherein the substantial partitioning surface of the partitioning electrode is biased toward the tube axis side with respect to the constriction of the triple circular hole.