JPH0472345B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron gun assembly for a cathode ray tube, and more particularly to an integrated single-row electron gun assembly.

Generally, the main lens aperture of a cathode ray tube electron gun affects the focus characteristics. In order to obtain good focus characteristics, the main lens aperture must be made as large as possible. This main lens aperture is limited by the electron gun structure of the cathode ray tube and the neck inner diameter of the neck glass tube that houses the electron gun.

In the case of an electron gun structure in which three electron beams are extracted from each independent electron gun, the main lens aperture is limited to about 30% of the net inner diameter. Below, the conventional integrated electron gun structure arranged in a row is shown in the first section.
This will be explained using FIG.

That is, the main lens electrode structure is the flat part 2 of the dish-shaped electrode 1.
A central cylindrical electron beam passage hole 3G and cylindrical electron beam passage holes 3R and 3B on both sides are bored in the center. The end edge 4 of the flat portion 2 is connected to a flange 6 via a side wall. The flange portion 6 is provided with a support piece that is implanted in the insulating support. Furthermore, each of the cylindrical electron beam passing holes 3
There is always a U-shaped part 8 between each cylinder of R, 3G, and 3B.
8' is formed. The U-shaped portions 8, 8' are provided so that the electrostatic lens formed in the center and the electrostatic lenses formed on both sides do not interfere with each other. It is generally preferable that the height of the U-shaped portion be approximately 1/3 or more of the diameter of the electron beam passage hole.

The width of the U-shaped portion cannot be made smaller than a certain level due to component processing, and this is a mechanical constraint that defines the diameter of the electron beam passage hole.

On the other hand, recently, one method of reducing the deflection power of cathode ray tubes is to reduce the inner diameter of the network, but since the main lens diameter of the electron gun naturally becomes smaller, this is one of the factors that causes deterioration of focus characteristics. It's summery.

Under these circumstances, high-definition cathode ray tubes have recently been put into practical use for displaying characters, graphs, etc. in addition to television images, and there is an increasing demand for improved focus characteristics.

As a plan to increase the diameter of the main electron lens, a continuous aperture in which three electron beam passing holes are connected to each other is provided in the flat part of the dish-shaped electrode, and the longitudinal center of the overlapping part of each electron beam passing hole is JP-A-56-82548 discloses a dish-shaped electrode structure in which a pair of shield plates are provided at a predetermined distance from a flat surface. However, in the above structure, although the astigmatism in the horizontal and vertical directions is eliminated, the shape of the electron beam passage hole at the position of the shield plate is not circular, and the shape of the central electron beam passage hole is It is rectangular and the electron beam passing holes on both sides are semicircular, resulting in a large difference in the shape of the three electron beams, which is insufficient in terms of improving focus characteristics.

The present invention has been made in response to such demands, and an object of the present invention is to provide an electron gun assembly capable of increasing the diameter of the main electron lens and improving focus characteristics.

In order to achieve this object, in the present invention, a continuous aperture in which a central electron beam passing hole and both side electron beam passing holes are connected to each other is bored in the flat part of the dish-shaped electrode, and the continuous aperture is A side wall extending from the periphery into the interior of the dish-shaped electrode is connected to three independent openings at a position projecting a predetermined distance from the flat part of the dish-shaped electrode.

The details of the present invention will be explained below.

3 and 4 show embodiments of the present invention. Third
As shown in the figure, the main lens electrode structure of the present invention is a dish-shaped electrode 11, and a central electron beam passage hole 13G and both side electron beam passage holes 1 are provided in the flat part 12 of the main lens electrode structure.
3R and 13B are drilled. Each of the three electron beam passing holes is circular, located on a straight line at a predetermined interval, and overlaps each other to form one continuous aperture. A second side wall 14 is provided so as to move away from the first side wall 110 toward the inside of the dish-shaped electrode 11 from the periphery of the continuous opening. This second side wall 14 has a slit-shaped taper, and has three independent electron beam passing holes 15R, 15G, 15 provided on a surface extending at a predetermined distance from the flat surface of the dish-shaped electrode 11.
It is connected to B. Independent central electron beam passage hole 15G and both side electron beam passage holes 15R, 15
V-shaped portions 16, 16' are formed between B.
The V-shaped portions 16, 16' are provided so that the electrostatic lens formed in the center and the electrostatic lenses formed on both sides do not interfere with each other.

FIG. 4 is a top view of FIG. 3, and shows the aforementioned continuous holes 13R, 13G, 13B, the second side wall 14, and three independent openings 15 provided at the edge of the side wall.
The electrodes other than R, 15G, and 15B are the same as the conventional electrodes, and their explanation will be omitted.

5 and 6 show another embodiment of the present invention. The main lens electrode structure is a dish-shaped electrode 21, and a central electron beam passage hole 23G and both side electron beam passage holes 23R and 23B are bored in the flat part 22 of the main lens electrode structure. and the three electron beam passing holes 23
R, 23G, and 23B are each circular, are arranged in a straight line at a predetermined interval, and overlap each other to form one continuous opening. A second side wall 24 is provided in parallel with the first side wall 210 from the periphery of the continuous opening toward the inside of the dish-shaped electrode 21 . This second side wall is connected to a flat part 22 of the dish-shaped electrode and a flat part 25 extending at a predetermined distance.
A central electron beam passage hole 26G and both side electron beam passage holes 26R and 26B are independently bored in the plane portion 25, respectively. Partition 2 between beam passage holes
7 and 27' are provided so that the electrostatic lens formed in the center and the electrostatic lenses formed on both sides do not interfere with each other.

FIG. 7 is a longitudinal cross-sectional view of a bipotential electron gun in which a dish-shaped electrode according to the present invention is incorporated. Three cathodes 31R, 31G, 31B first grid 32, second grid 33, third grid 34
and a fourth grid 35 are implanted and fixed to the glass pillar in this order. The main lens constituted by the third grid 34 and the fourth grid 35 is constructed by arranging the planar parts of two dish-shaped electrodes according to the present invention to face each other. With this configuration, as can be seen from the electric lines of force in FIG. 8, the aperture of the lens can be made larger than in the conventional lens, resulting in less spherical aberration.

In this way, in the present invention, the three independent apertures formed at the tip of the side wall extending inward from the periphery of the continuous aperture are circular, so that all three electron beams can have a substantially circular shape. .

On the other hand, as in the above-mentioned Japanese Patent Application Laid-open No. 56-82548, the apertures separated by a shiitake plate have a rectangular center and semicircular sides, so the electron beam passing through them is distorted due to the distortion of the electric field. It is not circular, and the distortion is different between the center and both sides, and the shape is not the same. In particular, since the central electron beam is distorted into a rectangular shape, the focus characteristics deteriorate, and when displaying figures that include line segments running diagonally, such as triangles and circles, the diagonal display lines are distorted in both horizontal and vertical directions. The display line becomes wider than the display line of , and the display quality deteriorates. Furthermore, if diagonal lines are displayed at a narrow pitch, they will become illegible, and the resolution will also deteriorate compared to the case where a substantially circular electron beam is used as in the present invention.

Furthermore, if the shapes of the electron beams at the center and both sides are different, when the electron beams are overlapped to produce a color as in a color CRT, for example, when the center beam and both side beams are overlapped to produce a certain color, different parts may protrude and cause the color to change. However, in the present invention, since the center electron beam and both side electron beams are substantially circular, the above-mentioned drawbacks are greatly improved.

In addition, in the same publication, the shield plate must be welded and fixed as a separate part, but in the present invention, it has a structure that can be integrally molded by press, and high dimensional accuracy can be achieved relatively easily. At the same time, it also has the effect of lowering manufacturing costs.

In the above description, the continuous holes are three circular holes that overlap each other, but they may also be ovals or polygons that overlap each other. Furthermore, the structure of the main lens is not limited to the bipotential type, but it goes without saying that the present invention is also applicable to a unipotential type or a multi-stage type lens that is a combination thereof.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are a longitudinal sectional view and a top view of a conventional dish-shaped electrode, respectively. 3 and 5 are longitudinal sectional views of the dish-shaped electrode according to the present invention. 4 and 6 are top views of the dish-shaped electrode according to the present invention.
FIG. 7 is a longitudinal sectional view of an electron gun assembly using a dish-shaped electrode according to the present invention, and FIG. 8 is an electric force line diagram of the main lens of the electron gun assembly. 11...Dish-shaped electrode, 12...Plane part, 110...
...first side wall, 14...second side wall, 15...electron beam passage hole.

Claims (1)

[Claims] 1. An electron gun assembly having a dish-shaped electrode including a flat part having an electron beam passage hole and a first side wall connected to an edge of the flat part and extending in the electron beam passing direction, The electron beam passing hole includes one continuous hole formed by intersecting three holes drilled in the planar portion, and the dish-shaped electrode spaced apart from the first side wall from the periphery of the continuous hole. An electron gun assembly for a cathode ray tube, comprising three independent circular apertures formed at a tip of a second side wall extending toward the inside of the electron gun at a position opposite to the continuous aperture.