JPS6131480Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron gun structure, particularly a multi-electron beam type electron gun structure.

In general, the electron gun assembly of a color picture tube consists of three electron guns made up of a plurality of grid electrodes.The main lens formed by the electron guns focuses the electron beam, and the electron beam is projected onto the screen. It is something that makes you However, since this electron gun assembly is composed of three electron guns, it is disadvantageous in terms of assembly work, and in recent years an electron gun assembly as shown in FIG. 1 has been proposed. In the figure, 1A, 1B, and 1C are first grids arranged in a Δ arrangement, and are equipped with cathodes or heaters. 2A, 2B, and 2C are the second grids. These first and second grids have the same configuration as the conventional one. 34 is a third grid, which is a combination of cup-shaped bodies forming the lower and upper grids 3 and 4. At the bottom of the cup-shaped body forming the lower grid 3, there is a convex portion 3 with a hole that protrudes into the inside of the second grid 2A, 2B, 2C.
2 is formed, and the bottom of the cup-shaped body forming the grid 4 is formed with three aperture holes, which will be described later. Reference numeral 5 designates a fourth grid, which has three aperture holes corresponding to the aperture holes in the Δ arrangement formed in the third grid 34. These grids 1, 2, 34, 5 are fixed to a bead glass support 6 at predetermined intervals. Note that the central axes 8 of the three electron guns are the central axes 8A, 8 of the respective Δ array holes.
It is parallel to B and 8C.

FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, showing the throttle holes 4A, 4B, and 4C formed in the upper grid 4 of the third grid 34. As is clear from the figure, aperture holes 4A, 4B, and 4C forming the main lens
are formed such that their centers are located at the vertices of an equilateral triangle. And this hole 4A, 4
It is desirable that B and 4C be large in order to reduce spherical aberration. The BB cross-sectional view of this aperture hole is the third one.
As shown in the figure, as is clear from the figure, the peripheral edges of the holes 4A, 4B, and 4C are pressed so as to have punched portions with a drawing depth h and an inner diameter D. The reason why the holes 4A, 4B, and 4C are made into narrow holes is to improve the withstand voltage characteristics and improve the symmetry of the electric field. The aperture holes 5A, 5B, and 5C formed in the fourth grid 5 also have the same shape as the aforesaid aperture holes.

However, when the third grid 34 and the fourth grid 5 having the aperture holes are arranged and used as shown in FIG. 4, the following drawback occurs. That is, if the third and fourth grids 34 and 5 are formed by cold working a non-magnetic stainless steel material containing, for example, Cr = 16% and Ni = 14%, the inner diameter D and the drawing depth of the drawing hole will change. The ratio h/D≦0.30, and it is difficult in processing to satisfy h/D≧0.5, which is the minimum requirement for effectively satisfying rotational symmetry. In other words, the drawing depth h is formed to be small. For this reason,
Holes 4A, 4B, 4C and 5 forming the main lens
The electric field near A, 5B, and 5C is strongly influenced by the sidewall X. The electric field affected by the side wall X in this way is caused by the holes 4A, 4B, 4C and 5A
Since the distances between 5B and 5C and the entire side wall X are asymmetrical, a non-uniform electric field results, and the main lens obtained from this electric field produces astigmatism, which impairs focus characteristics.

Accordingly, an object of the present invention is to provide an electron gun assembly that improves focus characteristics by forming a main lens that obtains a uniform electric field and does not produce astigmatism.

In order to achieve this purpose, the present invention arranges a member having a hole on the side of the grid electrode forming the main lens that does not face the main lens, and also includes a structure in which the mounting part of this member is held between the grid electrodes. This is what I did.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 5 is a cross-sectional view of one embodiment of the electron gun assembly according to the present invention, showing the same cross section as FIG. 4, and the same reference numerals are used for the same parts as in FIGS. 1 to 4.

In the figure, a plate-like body 40 constituting the bottom of a cylindrical body 41 has a mounting part 42 integrally provided in a flange shape on the outer periphery of the cylindrical body 41, which is sandwiched between the flange parts of the grids 3 and 4. arranged and fixed at exactly right angles to the tube axis 8, and
Diameter that has almost the same center as the aperture holes 4A, 4B, and 4C
It has holes 40A, 40B of d ₁ and 40C (not shown). Also, inside the fourth grid 5, there are holes 50A having a diameter d ₂ having almost the same structure as the plate-like body 40,
A plate-like body 50 having a hole 50B and a hole 50C (not shown) is arranged. This plate-like body 50 has a cylindrical body 51 and a mounting part 52 provided in the shape of a flange on the outer periphery. By overlapping and fixing the mounting part 52 to the flange part of the fourth grid 5, the plate-like body 50 body 5
0 is placed exactly at right angles to the tube axis 8.

According to such a configuration, the plate-like bodies 40, 5
0 acts to shield the electric field of the side wall
diameters d ₁ of l ₁ , l ₂ and holes 40A, 40B, 40C,
By appropriately selecting the diameter d ₂ of the holes 50A, 50B, 50C, the aperture holes 4A, 4B, 4C and 5
The influence on the electric field near A, 5B, and 5C can be reliably suppressed, and the focus characteristics can be improved. The above focus characteristics can be improved by making the above l ₁ and l ₂ equal to or less than the diameter D of the aperture holes 4A, 4B, and 4C, and the hole diameters d ₁ and d ₂ are set to diameters that allow most of the electron beams to pass through. If it is above, it can be arbitrarily determined, and the shape of the hole is l ₁ ,
If l ₂ > D, it can be set to any shape other than a circle. In other words, the distances l ₁ and l ₂ between the plate-like bodies 40 and 50
becomes smaller, the holes 40A, 40
B, 40C, and the holes 50A, 50B, and 50C should tend to be close to circular, and the l ₁ , l ₂ of the holes ≧
In the range D, the shape of the hole has less influence on the main lens, so it is not necessary to make it circular.

FIG. 6 is a sectional view showing another embodiment of the electron gun assembly according to the present invention, in which the same or corresponding parts as in FIG. 5 are denoted by the same reference numerals. In this embodiment, the mounting part 42 is manufactured separately from the plate-like body 40 and the cylindrical body 41 and combined, and the other structure is the same as that of the fifth body.
It is exactly the same as the figure.

In each of the embodiments, a bipotential type electron gun structure with a delta arrangement has been described, but the present invention can be similarly applied to an inline arrangement or a unipotential type electron gun structure.

Further, in the embodiment, plate-like members are arranged in both the third grid 34 and the fourth grid, but they may be arranged only in the third grid 34. Further, the holes formed in the plate-like body may have any shape, for example, each hole may be continuous with a slit.

As explained above, according to the present invention, a member having a hole through which the electron beam passes is arranged on the side of the grid electrode forming the main lens that does not face the main lens, and the mounting part of this member is held between the grid electrodes. Since the main lens is fixed to shield the electric field on the side wall, the member can be placed in an accurate position, improving the rotational symmetry of the electric field forming the main lens, and the main lens is free from astigmatism. , focus characteristics are improved. Therefore, when the electron gun assembly according to the present invention is applied to a color picture tube, it is possible to display a good image.

[Brief explanation of drawings]

Fig. 1 is a front view of a conventional electron gun assembly, Fig. 2 is a sectional view taken along line AA in Fig. 1, and Fig. 3 is a sectional view taken along line B-B in Fig. 2.
4 is a sectional view of an electron gun assembly, FIG. 5 is a sectional view of one embodiment of the electron gun assembly according to the present invention, and FIG. 6 is a sectional diagram of another embodiment. 3...Lower grid, 4...Upper grid, 3
4...3rd grid, 5...4th grid, 4
0,50... plate-shaped body, 41,51... cylindrical body, 4
2, 52...Mounting part, 40A, 40B, 50A,
50B...hole.

Claims (1)

[Scope of utility model registration request] In an electron gun assembly in which grid electrodes of the same potential are integrated by the same part and a main lens is formed by the opposing parts of these integrated grid electrodes, the side of at least one of the opposing grid electrodes that does not face the main lens A member having a hole through which the electron beam passes is arranged, and the mounting part of this member is clamped and fixed by grid electrodes, and the rotational symmetry of the electric field forming the main lens is improved by the member. Characteristic electron gun structure.