JPS6227498B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron gun for color picture tubes, and in particular, to problems with a single electron gun (unitizing gun) often used in automatic converging color picture tubes (self-converging color picture tubes). This relates to a structure for reducing point aberration.

The single electron gun, which is often used in automatic concentrating color picture tubes, is
As shown in the figure, 3 phosphors collide with red, green, and blue phosphors coated on the inner surface of the face plate.
The electrodes forming the electron beams 1, 2, and 3 of the book are each integrated. In particular, the assembly accuracy of the third electrode 21 and the fourth electrode 22 forming the main focusing lens is important, so they are integrated. The first electrode 19 and the second electrode 20 may be integrated or separated. In any case, in order to improve assembly accuracy, the first electrode 19,
Both electron beam holes 4, 7, 1 on the second electrode side and the fourth electrode 22 side of the second electrode 20 and the third electrode 21
Centers 4a, 7 of 0, 13 and 6, 9, 12, 15
a, 10a, 13a and 6a, 9a, 12a, 1
The line passing through 5a is substantially in line with the line passing through the centers 5a, 8a, 11a, 14a of the central through holes 5, 8, 11, 14, and is parallel to the tube axis (electron gun axis).

Both side electron beam holes 16 and 18 of the fourth electrode 22
The centers 16a and 18a of the third
Slightly (0.1 to 0.3
mm) shifted, three parallel electron beams 1, 2, 3
are the red, edge, and blue phosphors of the fluorescent screen 23 formed on the inner surface of the face plate (not shown).
It is designed to shoot at each. 24 in the figure,
25 and 26 indicate the center of the lens.

However, such an electron gun structure has serious drawbacks. That is, as shown in FIG. 2, the double-sided electron beams 1 and 3 formed by the first, second, and third electrodes (see FIG. 1) are formed by the third electrode 21 and fourth electrode 22. The electron gun axis line 100 is slightly (approximately 0.1 to 0.3 mm) not incident on the center of the main focusing lens.
Since it is shifted to the side, astigmatism 30, 31 occurs as shown in FIG. 27, 28, and 29 indicate the spot shapes of the electron beams.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and the present invention has been made in such a way that the electron beam incident on the main focusing lens passes through approximately the electron optical center of the main focusing lens. It is characterized by an array of forming holes.

Next, one embodiment of the present invention will be described using the drawings.

As shown in FIG. 4, the first embodiment has a triode section 50 consisting of a cathode (not shown), a first electrode 19, and a second electrode 20, and a third electrode 21 that has electron beams passing through both sides of the second electrode side. Centers 4a, 7a, 10a and 6a, 9a, 12a of holes 4, 7, 10 and 6, 9, 12
are arranged in a straight line, respectively, and the third electrode 2
Electron beam holes 13 and 15 on the fourth electrode 22 side of 1
The centers 13a, 15a of are slightly (0.1 to 0.3 mm) shifted toward the electron gun axis 100 side from the axes 200, 300 on both sides passing through the centers of the electron beam holes on both sides,
The centers 16a, 18a of the electron beam holes 16, 18 on both sides of the fourth electrode 22 are slightly shifted (0.1 to 0.3 mm) in the direction opposite to the electron gun axis. As a result, the electro-optical centers 24 and 26 of the main lens formed by the third and fourth electrodes are arranged so as to substantially coincide with the axes on both sides.

That is, between the third and fourth electrodes, the main focusing electron lens is formed at a position where each of the three electron beams passes through the center of a line connecting the centers of the opposing electron beam holes. Electron beam holes were provided on both sides of each of the opposing electrodes.

In the second embodiment, as shown in FIG.
Both electron beam holes 10 on the second electrode 20 side of 1,
12 are the electron beam holes 4 on both sides of the first electrode 19, the second electrode 20, and the third electrode 21 on the fourth electrode 22 side,
Centers 4a, 7a, 1 of 7, 13 and 6, 9, 15
This is a method of slightly (0.1 to 0.3 mm) shifting toward the electron gun axis side with respect to the straight line passing through 3a, 6a, 9a, and 15a. In the first embodiment, electron beams 1 and 3 on both sides
The trajectory is parallel to the electron gun axis up to the main electron lens, whereas in the second embodiment, it is slightly tilted outward with respect to the electron gun axis, and the trajectory of the main lens is substantially parallel to the electron optics of the main lens. The electron beam holes in the electrodes are arranged so that the electron beam passes through the target centers 24 and 26. In addition to this, as in the second embodiment, there are many possible methods in which the electron beams on both sides entering the main electron lens are slightly tilted outward with respect to the electron gun axis so that they pass through the substantial optical center of the main electron lens. . For example, the parallelism of the electrodes may be slightly changed, but a detailed explanation will be omitted.

Next, a third embodiment will be described which makes the method described above even more effective. In the case of a self-focusing color picture tube, the magnetic field distribution of the deflection yoke is strongly distorted in order to focus the three electron beams to approximately one point over the entire screen. That is, as is well known, the horizontal magnetic field is a strong pink tension magnetic field, and the vertical magnetic field is a strong barrel magnetic field.
Therefore, as shown in FIG. 6, the spot shape of the electron beam becomes an ellipse around the screen. This is called electron beam deflection aberration. For this reason, the focus quality (image quality) is significantly degraded. In order to alleviate this problem, a structure has already been proposed in which the through holes of the first electrode and the second electrode are made into an elliptical shape to compensate, but this structure has many problems in assembling parts.

The third embodiment of the present invention solves this problem. That is, this method utilizes the properties of static focusing permanent magnets (4-pole or 6-pole magnets) that are often used in automatic focusing color picture tubes.
For example, as shown in FIG. 7, when the electron beams on both sides are shifted inward (toward the electron gun axis side) by utilizing the non-uniformity of the quadrupole magnet, the electron beams are deformed into a substantially vertically elongated shape. This acts to compensate for the beam distortion (deflection aberration) caused by the above-mentioned deflection yoke. In order to apply this in design, the third electrode and the fourth electrode, which face each other to form the main electron lens, must be
The relative deflection of the electron beam holes on both sides of the electrode is made slightly smaller to reduce the convergence angle of the three electron beams when no deflection is performed. This is focused by the four-pole magnet mentioned above. The electron beam trajectory corrected by the quadrupole magnet is further shifted inward (towards the electron gun axis) from the electron optical center of the main lens. If the electron beam holes in each electrode are arranged with this in mind in advance, the electron beam will pass through the electron optical centers 24 and 26 of the main electron lens, as shown in Figure 8, and even more effects can be obtained. . In Figures 7 and 8,
41 indicates a permanent magnet or an electromagnet. This has the advantage that astigmatism and deflection aberration, which are disadvantages of automatic focusing color picture tubes, can be solved at the same time. Further, the electron gun for color picture tube of the present invention may have various structures within the scope of the gist, but it goes without saying that these are also included within the scope of the present invention.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the structure of a conventional integrated electron gun and the locus of the electron beam, and Fig. 2 is an explanatory diagram showing the pole arrangement of the main focusing lens section of the conventional integrated electron gun and the electric field and the trajectory of the electron beam. 3 is an explanatory diagram showing the spot shape of the electron beam on the screen by the integrated electron gun of FIGS. 1 and 2, and FIG. 4 is an electrode arrangement of the integrated electron gun of one embodiment of the present invention. Figure 5 is an explanatory diagram showing the electrode arrangement of an integrated electron gun according to another embodiment of the present invention and the trajectory of the electron beam. Figure 6 is the magnetic field distribution of the deflection yoke. FIG. 7 is a conceptual diagram showing the change in the cross-sectional shape of the electron beam caused by the quadrupole magnet, and FIG. 8 is a plan view showing the spot shape of the electron beam on the screen caused by the distortion of As an example, the seventh
FIG. 2 is an explanatory diagram showing an electron beam trajectory using an integrated electron gun when the quadrupole magnet shown in the figure is applied. 19...first electrode, 20...second electrode, 21...
...Third electrode, 22... Fourth electrode, 23... Shadow mask, 27, 28, 29... Electron beam spot shape.

Claims (1)

[Claims] 1. At least three electron beam apertures arranged substantially in a row for generating three electron beams arranged in a row at the center and on both sides and directing the electron beams toward a fluorescent screen of a picture tube. It has a main lens forming electrode consisting of a triode section including a first and a second electrode, and at least two third and fourth electrodes that are closer to the fluorescent screen than the triode section and form a main focusing electron lens. , the third electrode is a cylindrical electrode having three electron beam holes arranged in a row on each surface facing the second electrode and the fourth electrode; A cylindrical electrode having three electron beam holes arranged in a row on opposing surfaces, the phosphor screen side being open, the electron beam holes in the center of each other being arranged in a row along the electron beam traveling direction. An electron optical system of a main focusing electron lens that is on a straight line and in which each of the three electron beams is formed at the center of a line passing through the center of each opposing electron beam hole of the third and fourth electrodes. For a color picture tube, wherein the electron beam holes on both sides of the fourth electrode are disposed further outward than the electron beam holes on the fourth electrode side of the third electrode so as to pass through the center. electron gun. 2. In the main lens forming electrode, the centers of the electron beam holes on both sides of the third electrode on the triode side are on the axis of both sides passing through the centers of the electron beam holes of the first electrode and the second electrode, and The centers of both electron beam holes on the fourth electrode side are closer to the electron gun axis than the both axes, and the centers of the electron beam holes on both sides of the fourth electrode of the main lens forming electrode are closer to the electron gun axis than the both axes. An electron gun for a color picture tube according to claim 1, which is located away from the camera. 3 In the third electrode of the main lens forming electrode, the center of both electron beam holes on the triode side of the third electrode is closer to the electron gun axis than the both axes, and The centers of the electron beam holes on both sides are substantially on the axis of both sides, and the center of the electron beam holes on both sides of the fourth electrode of the main lens forming electrode is
The electron gun for a color picture tube according to claim 1, which is located at a position farther from the electron gun axis than the both-side axes. 4 Among the main lens forming electrodes, the third electrode has both electron beam holes on the triode side on the both-side axis, and the center of both electron beam holes on the fourth electrode side is on the above-mentioned axis. The centers of the electron beam holes on both sides of the fourth electrode of the main lens-forming electrode are located on the electron gun axis side of the both-side axes, and the asymmetric main focusing electron lens with a small deflection is located on the both-side axes. An electron gun for a color picture tube according to claim 1, wherein the electrode has magnetic auxiliary deflection means.