JPH0415978B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a color picture tube having an in-line array of three electron guns, and more particularly to the structure of a coma aberration correction element for equalizing the scanning area on a fluorescent surface. It is.

[Technical Background and Problems of the Invention] In general, a shadow mask type color picture tube has an in-line array of three electron guns arranged in a line corresponding to the horizontal axis of a substantially rectangular effective image plane. The three electron beams in an in-line arrangement, namely a central beam and a pair of side beams, are deflected by a horizontal deflection magnetic field perpendicular to the horizontal axis and a vertical deflection magnetic field parallel to the horizontal axis, and are substantially positioned on the fluorescent surface. scan a rectangular area. It is necessary that the three scanning areas by these three electron beams overlap and match accurately on the fluorescent surface, but in reality, there may be slight deviations due to various problems such as the arrangement of the electron beams and the rectangular scanning area. will occur. In order to correct such deviations, for example, as shown in Japanese Patent Publication No. 51-44046, the final electrode of the electron gun, the so-called convergence cup electrode, receives horizontal and vertical deflection magnetic fields to utilize an enhancement or shaft effect. A means for arranging coma aberration correction elements made of a magnetic material is known.

Figures 1 and 2 show an example of such a coma aberration correcting element, with a convergence cap of 1.
There are three electron beam passing holes 2-R, 2- at the bottom of the electrode.
G and 2-B are provided, and coma aberration correction elements 3-B and 3-R are provided so as to surround the side electron beam passing holes 2-B and 2-R. The coma aberration correction elements 3-B and 3-R are configured to have portions parallel to the horizontal and vertical deflection magnetic fields, respectively, so that the correction action can be performed effectively. still,
FIG. 2 is a schematic diagram showing a cross section of FIG. 1. This coma aberration correction element must be accurately mounted at a predetermined position, and the mounting in this case is performed as follows. That is, the coma aberration correction element is centered with respect to the electron beam passage hole using a round bar-shaped jig having an outer diameter approximately equal to the inner diameter of the electron beam passage holes 2-B and 2-R. A block-shaped tool is placed between -B and 3-R, and the horizontal axis (X-X)
The parallelism with respect to the vertical axis (Y-Y) and the tube axis (Z-Z) is adjusted and finally fixed by welding or the like.

However, this mounting method requires precise jigs and tools, and if the diameter of the net in which the electron gun is installed is reduced, the jigs and tools must be made very small, making it difficult to fix by welding. At the same time, the mechanical strength and precision of the jigs and tools become a problem, making them more expensive and requiring more effort to maintain and manage.

In addition, especially in the case of an electron gun with an ultra-thin neck diameter and a large-diameter lens, electron beam passing holes 2-R, 2
-G and 2-B also naturally have large apertures, and there is almost no free space for attaching the coma aberration correction element to the bottom of the convergence cup 1 electrode, and the coma aberration correction element with the shape shown in Fig. This also causes the problem that aberrations are insufficiently corrected.

[Object of the Invention] The present invention has been made in view of the above points, and provides a color picture tube in which a coma aberration correcting element can be easily and accurately attached without the need for jigs and can sufficiently correct coma aberration. The purpose is to obtain.

[Summary of the Invention] The present invention provides a coma aberration correction element having a first contact portion that is in contact with an electrode plane having an electron beam passage hole, and a wall of the electron beam passage hole that extends from the first contact portion in the electron beam passage direction. and a second contacting part that is in contact with the electrode, and a guide part provided between the first or second contacting part and the electrode allows the horizontal axis (X-X) and the vertical axis (Y-Y) to be The position is regulated in all directions along the tube axis (Z-Z), and the coma aberration correction portion in the tube axis direction is increased to enable sufficient correction.

[Embodiments of the Invention] Examples of the present invention will be described below with reference to FIGS. 3 and 4. Incidentally, FIG. 4 is a schematic diagram showing a cross section of FIG. 3.

Large diameter electron beam passing holes 12-R, 12-G and 12-B are provided on the electrode plane at the bottom of the convergence cup 11. Passing holes 12-B and 12 on both sides of the pair of electron beam passing holes
-R is provided with arc-shaped guide portions 14-B and 14-R that respectively protrude toward the center of the opening.

The coma aberration correcting elements 13-B and 13-R are in contact with an electrode plane having an electron beam passage hole and have first contact parts 15-B and 15-R, respectively, which have portions parallel to the horizontal deflection magnetic field, through which the electron beam passes. It is composed of second contact portions 16-B and 16-R that are in contact with the hole wall.

The second contact portions 16-B and 16-R that are in contact with the wall of the electron beam passage hole are connected to the electron beam passage hole 12.
- Guide portion 14-B provided in B and 12-R
and 14-R, and the cylindrical portion is provided so as to extend in the tube axis (Z-Z) direction.

That is, the second contact portions 16-B and 16-R that are in contact with the wall of the electron beam passage hole 12
-B and 12-R have guide portions 14-
The position is regulated by B and 14-R. On the other hand, the outer diameters of the cylindrical portions of the second contact portions 16-B and 16-R are formed so as to fit smoothly into the inner diameters of the electron beam passage holes 12-B and 12-R, so that they are opposed to the electrode plane. The position is restricted together with the first contact portions 15-B and 15-R that are in contact with each other.

Such coma aberration correction elements 13-B and 13
-R is attached to a cylindrical shape that constitutes the second contact portions 16-B and 16-R that are in contact with the wall of the electron beam passage hole in accordance with the guide portions 14-B and 14-R provided in the electron beam passage hole. All positions of the horizontal axis (X-X), vertical axis (Y-Y), and tube axis (Z-Z) can be accurately adjusted without using jigs by simply sliding the part into the electron beam passage hole. Can be regulated.

Furthermore, by adjusting the length extending in the tube axis (Z-Z) direction of the cylindrical portions constituting the second contact portions 16-B and 16-R that are in contact with the electron beam passage hole wall, coma aberration can be reduced. It becomes possible to sufficiently compensate for the shortfall in correction.

In the above embodiments, a cylindrical part as a second contact part extending in the electron beam passing direction of the coma aberration correction element and facing the wall of the electron beam passing hole and a guide part provided in the electron beam passing hole are used. I gave an example, but
The present invention is not limited to this, and other separate position regulating holes or beads may be provided at the bottom of the electrode as a guide part, and the central electron beam passing hole may be used as long as it does not affect the coma aberration correction function. Various configurations may be adopted without departing from the spirit of the present invention.

[Effects of the Invention] As described above, according to the present invention, it is possible to easily and accurately mount a coma aberration correction element without using jigs and tools, and it is also possible to sufficiently correct coma aberration. Suitable for color picture tubes having electron guns with aperture electron lenses.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing how a conventional coma aberration correction element is installed, FIG. 2 is a schematic sectional view of FIG. 1, and FIG. 3 is a first embodiment showing an embodiment of the present invention.
FIG. 4 is a schematic front view corresponding to the figure, and FIG. 4 is a schematic sectional view of FIG. 3 as well. 11... Convergence cap, 12-B, 1
2-G, 12-R...Electron beam passing hole, 13-
B, 13-R... coma aberration correction element, 14-B,
14-R...Guide part, 15-B, 15-R...
Opposing portion, 16-B, 16-R...Cylindrical opposing portion.

Claims (1)

[Claims] 1. An in-line array 3 electron gun that emits a central electron beam and a pair of side electron beams arranged in a line along a horizontal axis, and at least one of the electrodes constituting the electron gun has a scanning area for the 3 electron beams. In a color picture tube equipped with a coma aberration correction element that corrects the coma aberration to be equal, the coma aberration correction element has a first opposing portion that is in contact with an electrode plane having an electron beam passage hole and has a portion that is parallel to the horizontal deflection magnetic field. and a second opposing portion that extends from the first opposing portion in the electron beam passing direction of the electrode and contacts the wall of the electron beam passing hole, the first or second opposing portion of the coma aberration correction element. A color picture tube characterized in that a guide part is provided between the part and the electrode for regulating the position of the electron beam passage hole in the circumferential direction.