JPH0346735A - Electron gun for color picture tube - Google Patents

Abstract

PURPOSE:To prevent the deformation of a plate-like electrode at the time of assembly by crossing the end part of the plate-like electrode with the straight line part of a tubular electrode, and forming a cross point to the inner side in a long axis direction from the intersection point of the straight line part and a semicircle part of the tubular electrode. CONSTITUTION:A circular arc part 81a of a tubular electrode 81 is made R2 larger than l1, a intersection point D of a straight line part 81b and the circular arc part 81a is separated by a dimension d from a cross point H of a end part 82a of a plate-like electrode 82 and the straight line part 81b of the tubular electrode 81, and the straight line part 81b is formed in the opening of both side beams. Moreover a straight line part 12a receiving one part of a straaight line part 81b' is formed to a mandrel jig 12. Since the straight lines part 81b' of a G4 electrode is received with the straight line part 12a of the mandrel jig 12 at the time of electrode assembly, a rotation component for the mandrel jig 12 is unoccurring in the G4 electrode. Moreover the hitting of the plate-like electrode 82 is eliminated when the G4 electrode is inserted, and deformation can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electron gun for a color picture tube, and more particularly to an electrode structure constituting a main lens of an in-line electron gun.

[Conventional technology]

Generally, a color picture tube equipped with an in-line electron gun has a structure as shown in FIG. That is, in the glass envelope 1, a phosphor screen 2 in which phosphors of three colors are coated in pomelo-like stripes is formed on the inner wall of the face plate portion 1a, and a conductive film 3 is formed on the inner wall of the funnel portion 1b. There is. Inside the neck IC of the glass envelope l, there are three cathodes 4A, 4B, 4C, G and an electrode 5 arranged in-line.
, a Gt electrode 6, a G electrode 7, a G4 electrode 8, and a shield cup 9. Opening portions are formed in these electrodes 5 to 8 and shield cup 9 so as to correspond to the cathodes 4A to 4C and to be substantially parallel to each other on a common plane with the central axes 10A to IOC of the cathodes 4A to 4C. Here, G, electrode 7
G is set to a lower potential than the electrode 8, and the high potential electrode 8 is at the same potential as the conductive film 3 and the shield cup 9.

Further, on the outside of the seven-channel portion 1b of the glass envelope 1, there are provided three electron beams emitted from the cathodes 4A to 4C and passed through the electrodes 5 to 8 and the shield cup 9 for scanning the phosphor screen 2. An external magnetic deflection yoke 11 is provided.

The G3 electrode 7 and the regular G4 electrode 8 constitute the entire lens, and the G electrode 7 and the G4 electrode 8 are oval-shaped cylindrical electrodes 71 and 81 and inner walls 71a of the cylindrical electrodes 71 and 81.
and a flat plate electrode 72 fixed to 81a by spot welding or the like.
and 82.

By the way, to assemble the main lens part, as shown in FIG. Spacer(
(not shown), and the heated and softened multiform glass 13 and the like are welded and fixed to the mounting portions of the electrodes 5 to 8, and assembled.

Now, in a color picture tube with such a structure, C.
As an example of a main lens with a large aperture diameter, the one shown in Japanese Patent Laid-Open No. 59-215640 is known. The 04 electrode 8 having this structure is shown in FIG. That is,
Cathode central axis 10A.

10B, the corresponding points on the IOC are Q, P, 0
Then, the short side of the cylindrical electrode 81 in the horizontal direction is at point 0, Q
It is formed into a circular arc portion 81a surrounded by a radius R1 centered at
It is formed by straight portions 81b spaced apart by 31. here,! , = R1, so the straight portion 81b
The intersection of the arc portion 81a and the arc portion 81a is perpendicular to the straight line S and is a point 0. Q
Exists on vertical lines E and F passing through.

On the other hand, the plate electrode 82 has a cylindrical electrode 8 at both ends in the horizontal direction.
1, only the aperture through which the central beam passes is formed, and the side beam apertures on both sides are connected to the plate electrodes 82.
It is desirable to make the end portion 82a and the cylindrical electrode as large as possible.

ing.

Although illustration and description are omitted, the G electrode 7 has almost the same structure as the G4 electrode 8.

As a result, the effective aperture diameters of the G, electrode 7 and G4 electrode 8 can be sufficiently expanded, and the focusing characteristics of the color picture tube are improved.

[Problem to be solved by the invention]

In the structure of the G electrode 7 and the G electrode 8 shown in the above-mentioned prior art, when the G3 electrode 7 and the G electrode 8 generate mutually trapped rotational components in the horizontal direction, the beam passing central axis 10A, IO
B. Axis misalignment occurs with respect to the IOC, resulting in distortion in the main lens, increased lens aberration, and deterioration of focus characteristics. In order to minimize this as much as possible, the core metal jig 12 is arranged so that the arcuate portions 71 of the cylindrical electrodes 71 and 81 of the G, electrode 7 and G4 electrode 8, as shown in FIG.
a, 81a.

In this way, in the conventional structure of the G electrode 7 and the G4 electrode 8, the rotation of the G electrode 7 and the G4 electrode 8 is controlled by aligning the core metal jig 12 with the circular arc portions 71a and 81a of the cylindrical electrodes 71 and 810. Since it is necessary to prevent such problems, the following problems arise.

Now, looking at the G4 electrode 8, as shown in FIG.
When the plate-shaped electrode 82 is fixed to the cylindrical electrode 81 with an axial deviation of δ from the center line SK of the cylindrical electrode 81, the end G of the plate-shaped electrode 82 protrudes from the ID point by δ. When such a G4 electrode 8 is pushed into the metal core jig 12, the protrusion E of the plate electrode 82 comes into contact with the metal core jig 12 and is deformed, causing the main lens part to be locally distorted. This also deteriorates focus characteristics.

This deformation of the electrode was discovered after the electrode assembly was completed.
The method of checking this deformation is difficult, and it is unavoidable that mass production would be extremely expensive.

Furthermore, misalignment between the cylindrical electrode and the plate electrode can be checked at the component stage, but it is difficult to completely eliminate the potential of the electrode to be inserted at right angles to the metal core jig.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electron gun for a color picture tube that can prevent deformation of plate electrodes during assembly and stabilize focus characteristics.

[Means to solve the problem]

In order to achieve the above purpose, only an elliptical cylindrical electrode whose major axis is the alignment line of the three electron beams and an aperture fixed inside this cylindrical electrode through which the central beam passes are formed. In the electrode for forming a main lens formed by surrounding the side beam apertures on both sides with the ends of the plate-like electrode and the cylindrical electrode, the cylindrical electrode is formed at the end of the plate-like electrode. intersect with the straight part of the cylindrical electrode, the intersection point is formed inward in the long axis direction from the intersection of the straight part of the cylindrical electrode and the semicircular part of the cylindrical electrode, and in the side beam opening. It has a straight section.

[Effect]

Since the openings of both side beams have straight portions, rotation of the electrode with respect to the core metal jig is prevented by receiving a portion of the straight portions with the metal core jig. In addition, the core metal jig can be manufactured so that the intersection point between the end of the plate electrode and the straight part of the cylindrical electrode does not hit the core metal jig. deformation is prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. The same or equivalent parts as in FIGS. 3 to 7 will be described with the same reference numerals. In this embodiment, the plate-shaped electrode 82 is formed in the same manner as the conventional one, and the cylindrical electrode 81 has a circular arc portion 81a on the short side.
It is formed with a radius R7 larger than 1. As a result, the intersection of the straight part 81b of the cylindrical electrode 81 and the circular arc part 81a is the same as that of the end 82a of the plate-shaped electrode 82 and the straight part 8 of the cylindrical electrode 81.
A straight portion 81b is formed in the aperture of both side beams at a distance of 6 dimensions from the intersection point H with 1a.

Therefore, by forming a straight part 12a on the core jig 12 to receive a part of the straight part 81b', the straight part 81b of the G4 electrode 8 is received by the straight part 12a of the core jig 12 during electrode assembly. Therefore, no rotation component occurs in the G4 electrode 8 with respect to the metal core jig 12. In addition, since the core metal jig 12 can be manufactured avoiding the intersection point H, G, electrode 8
The plate-shaped electrode 82 does not come into contact with the plate electrode 82 when it is inserted, and deformation is prevented.

FIG. 2 shows another embodiment of the invention. In this embodiment, contrary to the previous embodiment, the cylindrical electrode 81 is formed in the same manner as in the conventional case, and the intersection point H of the plate-shaped electrode 82 is located inward in the horizontal (long axis) direction by one dimension from the intersection point. It is formed like this. That is,
The horizontal dimension U of the plate-like electrode 82 is shorter by 2T than the conventional one.

As a result, the openings of both side beams have straight portions 81b9.
is formed.

Therefore, the straight part 81 is attached to the core metal jig 12 in the same manner as in the above embodiment.
By forming the straight portion 12a that receives b', the same effect as in the embodiment described above can be obtained.

By the way, in the case of this embodiment, if one dimension is made too large, the main lens will be distorted, and conversely, the focus characteristics will be deteriorated. As a result of prototype confirmation,
In the case of R, = 4 m, T = 0.5 to 1.0
No side effects were observed until Seiho.

Although the above embodiment has been described with reference to the case where the present invention is applied to the G4 electrode 8, the same effect can be obtained even when the present invention is applied to the G4 electrode 7. Furthermore, although the explanation has been given using a pi-potential electron gun as an example, similar effects can be obtained with other uni-potential electron guns, multi-stage electron guns, and the like.

〔Effect of the invention〕

According to the present invention, rotation and deformation of the electrodes during electrode assembly can be prevented, so lens aberrations occurring in the main lens portion can be reduced, and focus characteristics can be stabilized.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a main part showing one embodiment of the present invention, Fig. 2 is a sectional view of a main part showing another embodiment of the invention, and Fig. 3 is a conventional in-line type force 2 - horizontal direction of the picture tube. 4 is a vertical sectional view showing the assembly of the main electrode portion of the electron gun in FIG. 3, FIG. 5 is a sectional view taken along line A--A in FIG. 4, and FIG. FIG. 5 is a sectional view of the main part, and FIG. 7 is a cross-sectional view of the main part in a state where the plate electrode is shifted. 7...G, electrode, 71...cylindrical electrode, 72...
・Plate electrode, 8...G, electrode, 81...cylindrical electrode, 81a...arc part, 81b, 81b°...
・Straight line part, 82...Plate electrode, 82a...End part, D...Intersection point, H...Intersection point. Figure 81b, 81b': Straight line H: Crossing

Claims (1)

[Claims] An oval cylindrical electrode whose major axis is the alignment line of one or three electron beams, and a plate-shaped electrode fixed inside the cylindrical electrode with only an opening through which the central beam passes. has
In an electron gun for a color picture tube equipped with an electrode for forming a main lens formed by surrounding side beam apertures on both sides with an end of a plate-shaped electrode and a cylindrical electrode, the end of the plate-shaped electrode is surrounded by the cylindrical The intersection point is formed inward in the long axis direction from the intersection of the straight part of the cylindrical electrode and the semicircular part of the cylindrical electrode, and the straight line is made to intersect with the side beam aperture. An electron gun for a color picture tube, characterized in that an electron gun is provided with a section.