JPS638049Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron gun assembly for an in-line color picture tube, and more particularly to an improvement in a magnetic field control element disposed at the leading edge of the electron gun.

In a color picture tube with three electron beams arranged in-line, the size of the raster drawn on the phosphor surface by an external magnetic deflection yoke is determined by the center of the three electron beams due to the deflection of the side beams in the yoke magnetic field. Although the electron beam and the side electron beam are different, in order to correct this difference, the electron gun is provided with a magnetic field control element made of a magnetic material.

FIG. 1 is a perspective view showing an example of a conventional magnetic field control element, in which 1c is a central electron beam passage hole, 1a and 1b are side electron beam passage holes,
Reference numerals 2 and 3 indicate magnetic field control elements made of magnetic material, which are attached to the leading edge of the electron gun, that is, to the fluorescent surface side of the electron gun.

The details of the magnetic field control elements 2 and 3 will be explained based on one of the control elements 2. A plane portion 2b each extending outward and having a plane substantially perpendicular to the main wall 2a, and a pair of sub-plane portions 2b rising from the plane portion 2b and having planes perpendicular to the plane portion 2b and the main wall 2a, respectively. This sub-wall 2c has a side electron beam passage hole 1.
They are placed above and below a. Note that the other magnetic field control element 3 also has the same structure. Also 4
5 is a horizontal deflection magnetic field, and 5 is a vertical deflection magnetic field, which deflects each electron beam in the horizontal direction and the vertical direction, respectively.

Looking at the relationship between these magnetic fields and the magnetic field control elements 2 and 3, the main walls 2a and 3a are arranged to face the vertical deflection magnetic field 5, and the sub walls 2c and 3c are arranged to face the horizontal deflection magnetic field 4. It's summery. Next, looking at the vertical deflection magnetic field, the side electron beam passing hole 1
The magnetic fields in a and 1b are concentrated and weakened, especially on the sub-walls 2c and 3c of the magnetic field control elements 2 and 3, and the raster of the side electron beam becomes smaller in the vertical direction. The magnetic field hardly changes within the central electron beam passage hole 1c, so the raster of the central electron beam does not change. In this way, the raster of the center electron beam and the raster of the side electron beams can be made to match on the screen by the magnetic field control element.

The above is an example of a conventional magnetic control element and its operation.However, in such a structure, when a horizontal deflection magnetic field passes through the sub-walls 2c and 3c of the magnetic control elements 2 and 3, it is generated in a direction that obstructs the deflection magnetic field. Due to the eddy current, a magnetic field in the opposite direction to the horizontal deflection magnetic field 4 is generated inside the side electron beam passage holes 1a, 1b. on the other hand,
Since such a phenomenon does not occur inside the central electron beam passage hole 1c, there is a raster misalignment on the screen as shown in FIG. This has the disadvantage that convergence quality deteriorates.

If the sub-walls 2c and 3c are simply eliminated in order to solve this drawback, the degree of concentration of the vertical deflection magnetic field will be reduced, and the raster size correction will not be sufficient, which will also result in deterioration of the convergence quality.

Note that the vertical deflection magnetic field 5 also passes through the main walls 2a, 3a of the magnetic field control elements 2, 3, but since the frequency of the vertical deflection magnetic field is low, the generation of eddy current is small and the above problem can be ignored.

In order to solve the above-mentioned drawbacks, the present invention improves the magnetic field control element, eliminates the plane facing the horizontal deflection magnetic field, and creates an electron gun structure that can correct the raster size of the three electron beams. This is what we provide. Below, the present invention will be explained based on the embodiment shown in the drawings. Fig. 3 is a diagram of a part corresponding to Fig. 1 showing an embodiment of the present invention, and the same parts as Fig. 1 are the same. Symbols are given and detailed explanations are omitted.

In FIG. 3, the magnetic field control elements 12, 13 have main walls 12a, 13a and flat plate parts 12b, 13b.
has the same configuration as the conventional one, but the sub walls 12c and 13c
stands up parallel to the main walls 12a, 13a, and has a structure parallel to the horizontal deflection magnetic field 4. In other words, the structure is such that it faces the vertical deflection magnetic field 5. The other basic operations are the same as the conventional magnetic field control element, but the sub-walls 12c,
13c does not intersect with the horizontal deflection magnetic field, so no problematic eddy current flows, and since it is orthogonal to the vertical deflection magnetic field, the magnetic field can be concentrated and weakened, making it possible to correct the raster size. The amount of correction can be changed by changing the dimensions of the sub-walls 12c and 13c.

In the embodiment shown in FIG. 3, a magnetic field control element having a sub-wall at the tip of the flat plate part has been described, but the position of the sub-wall is not limited to this part, for example, the fourth
The operation is the same even if it is located in the middle of the flat plate portions 12b and 13b as in the example shown in the figure.

Further, FIG. 5 shows another example of the sub-walls 12c and 13c, and is a view seen from a direction parallel to the horizontal deflection magnetic field. Figures 5a and 5b have projections provided on a part of the flat plate part, and Figure 5c shows another member fixed by means such as welding.

As described above, the present invention not only makes it possible to match the raster sizes of the center electron beam and side electron beams, but also has the characteristics of completely eliminating raster deviations caused by eddy currents in the horizontal deflection magnetic field. be.

[Brief explanation of the drawing]

1 and 2 are diagrams for explaining the difference in raster size from the conventional magnetic field control element. FIG. 5 is a diagram showing an example of a sub-wall. 1...Electron beam passing hole, 2, 3, 12, 13
...Magnetic field control element, 2a, 3a, 12a, 13a
...Main wall, 2b, 3b, 12b, 13b...Flat plate part, 2c, 3c12c, 13c...Sub-wall, 4...
Horizontal deflection magnetic field, 5... Vertical deflection magnetic field.

Claims (1)

[Scope of utility model registration request] In an in-line electron gun structure that has a magnetic field control element on the tip side of the electron gun, a main wall is arranged between the central electron beam and both side electron beams and facing the vertical deflection magnetic field, and a main wall is arranged a predetermined distance outward from the main wall. 1. An in-line electron gun assembly comprising a magnetic field control element having sub-walls spaced apart from each other in the direction, substantially parallel to the side electron beam, and disposed above and below the side electron beam.