JPH0127547B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an in-line color picture tube that exhibits good resolution characteristics.

In general, the resolution of a color picture tube depends on the size and shape of the beam spot appearing on the phosphor screen surface, and in order to obtain good resolution characteristics, the beam spot should be as small as possible and with little shape distortion. becomes important. It is also important that the three electron beams converge correctly at any one point on the phosphor screen surface.

If the mutual spacing between the three electron beams passing through the deflection magnetic field is small, convergence adjustment becomes easier, but this requires reducing the diameter of the electron beam passage hole in the main lens generation electrode, which reduces lens aberration. Distortion increases and resolution decreases.

The present invention provides an in-line color picture tube in which the distance between three electron beams can be set small while the electron beam passing hole of the main lens forming electrode is set relatively large, and this is shown in the drawings below. This will be explained in detail along with examples.

In FIG. 1, the three cathodes 1, 2, and 3 arranged in a horizontal line are a _G1 electrode 7 having vertically slotted beam passage holes 4, 5, and 6, and a circular beam passage hole 8, 9, and 10. A bipotential electron gun is constituted by a G ₂ electrode 11 having a shape, a box-shaped G ₃ electrode 12, and a box-shaped G ₄ electrode 13. The G ₃ electrode 12 and the G ₄ electrode 13, which serve as main lens generation electrodes, have horizontally long rectangular openings 14 and 15 on mutually opposing surfaces, respectively _.
The internal space of the electrode 12 and the internal space of the _G4 electrode 13 are defined by two metal partition plates 16, 17, 18,
Each section is divided by 19.

The operation of the G ₃ electrode 12 and the G ₄ electrode 13 will be explained with reference to FIG _{. 2.} FIG.
, and c is a cross-sectional view taken along line A-A' of
B′ cross-sectional view. The internal space of the G ₃ electrode 12 is horizontally divided into three by partition plates 16 and 17, and the internal space of the G ₄ electrode 13 is divided into three by partition plates 18 and 19, respectively. However, G ₃ electrode 12
Since the horizontal length h of each of the lens spaces 20, 21, and 22, which are divided spaces within the lens space, is smaller than the vertical length v, the lens spaces are vertically long rectangular lenses. The relatively short horizontal length h is useful for shortening the distance between the main lenses, and the relatively long vertical length v is useful for securing a vast lens space.

However, since the lens electric fields generated in the lens spaces 20, 21, and 22 are not axially symmetric, the strength of the lens action differs in each of the horizontal, vertical, and diagonal directions, and the beam spot appearing on the phosphor screen surface is significantly affected. Produces asymmetric haze. Therefore, as shown in FIGS. 2b and 2c, the partition plates 16, 17,
8 and 19 do not start from each end face of the openings 14 and 15, respectively, but enter a certain distance inside, that is, near the respective opening end faces 23 and 24.
It is set up to avoid. Therefore, the distance f between the tip of the partition plate 17 of the G ₃ electrode 12 and the tip of the partition plate 19 of the G ₄ electrode 13 is larger than the gap g between the end surface of the aperture 14 and the end surface of the aperture 15, and the main lens ,
Lens space 20, 21 divided into three in the horizontal direction,
22, 25, 26, and 27, and near the opening end faces 23 and 24 of the horizontally long space that are not subjected to such division.

In general, the lens effect becomes stronger as the aperture width or electrode spacing becomes smaller, so the lens effect in a divided space where the horizontal length h is smaller than the vertical length v is as follows:
It is stronger in the horizontal direction than in the vertical direction. On the other hand, the lens action in the vicinity of the opening end faces 23 and 24 of the horizontally elongated space is stronger in the vertical direction than in the horizontal direction, so by combining both, the strength of the lens action in the horizontal direction and the strength of the lens action in the vertical direction are It is possible to equalize the Note that the broken line curve 28,
29 and 30 and 31 show typical examples of equipotential lines occurring in the vertical section and the horizontal section, respectively.

The horizontally long opening 14 of the _G3 electrode 12 is not rectangular,
As shown in FIG. 3, if a straight line 32 and a circular arc 33 are formed into an elliptical shape (oval shape), and the horizontally elongated opening 15 of the _G4 electrode 13 is also formed into a similar oval shape, the main High-order aberrations caused by the lens can be reduced, and the beam spot shape of the electron beams on both sides can be made good.

As has become clear from the above description, the in-line color picture tube of the present invention has horizontally long rectangular or oval openings on the opposing surfaces of the two main lens generating electrodes, and
The space inside the electrode following this aperture is horizontally divided into three parts by a partition plate, avoiding the vicinity of the aperture, and three vertically long lens spaces are formed here, resulting in good convergence and high resolution. can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an electron gun of an in-line color picture tube embodying the present invention, FIG. 2a is a front view of the _G3 electrode of the color picture tube viewed from the _G4 electrode side,
Figure b is a cross-sectional view taken along line A-A' in figure a, Figure c is a cross-sectional view taken along line B-B' in figure a, and Figure 3 is a front view of a main lens generating electrode according to another embodiment of the present invention. It is. 7...G ₁ electrode, 11...G ₂ electrode, 12...G ₃
Electrode, 13...G ₄ electrode, 14, 15...Horizontally long opening, 23, 24...Near the opening end surface, 16, 1
7, 18, 19... partition plate, 20, 21, 22,
25, 26, 27...lens space.

Claims (1)

[Claims] 1. Each of the opposing surfaces of the two electrodes for generating a main lens has a rectangular or oval-shaped opening that is long in the horizontal direction, and the space inside the electrode following this opening is horizontally moved by a partition plate, avoiding the vicinity of the opening. An in-line color picture tube characterized in that it is divided into three parts and three vertically long lens spaces are formed therein.