JPH06236737A - Focusing electrode of electron gun for color cathod-ray tube - Google Patents

Abstract

PURPOSE: To solve the astigmatism and improve the productivity by installing an electrode in which three electron beam through holes are unitedly formed and a main lens electrode installed in the screen face and having a diameter in the vertical direction whose upper and lower parts are curved. CONSTITUTION: Three electron beam through holes 7 are unitedly formed in an electrode 6 and a main lens electrode 8 having a diameter B' in the vertical direction whose upper and lower parts are curved is connected and fixed in the front face part of the electrode 6. The diameter B' is so made as to be 47% or more to the diameter A in the horizontal direction. Consequently, without requiring auxiliary electrode installation separately, the assembling process is made easy and the productivity is improved. Further, the astigmatism caused as the difference of the diameter in the horizontal direction and the diameter in the vertical direction of the main electrode becomes wide can be eliminated and deterioration of focusing property can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun for color cathode ray tubes, and more specifically, to improve the structure of the main electrode to prevent the focus characteristic from deteriorating as the screen portion becomes larger and the screen becomes longer. The present invention relates to a focus electrode of an electron gun capable of performing the above.

[0002]

2. Description of the Related Art Generally, an electron gun for a color cathode ray tube is
It emits an electron beam and focuses it on a screen coated with a phosphor to form spot-shaped pixels.

There is a standard such that the diameter of the neck portion of the funnel in which the electron gun which fulfills the above-mentioned role is enclosed is 22 mm, 29 mm or 32 mm.

FIG. 1 shows a cross-sectional state of the main electrode 2 side in which the electron gun is enclosed in the neck portion 1 of 29 mm.

Inside the main electrode 2, an auxiliary electrode 4 as shown in the sectional view of FIG. 2b is provided so that three electrode beam through holes 3 are formed.

It is more advantageous to make the diameter of the main lens of the main electrode 2 as large as possible in order to improve the focus characteristic of the electron beam emitted from the electron gun.

At this time, the main lens diameter of the large-diameter main electrode is
A certain distance must be maintained so as not to contact the inner surface of the neck portion 1.

This is to prevent discharge from occurring between the electron gun and the inner surface of the neck portion 1. That is, in a cathode ray tube with a neck portion 1 having a diameter of 29 mm, the long side of the main electrode 2 is located in the lateral direction of the neck portion 1, and the short side of the main electrode 2 is arranged in the vertical direction along with the plurality of electrodes of the electron gun. A beat glass 5 for fixing the components at equal intervals is provided.

At this time, in FIG. 1, when the diameter of the neck portion 1 is 29 mm, the outermost circumference of the main electrode 2 is provided so that the dimension in the lateral direction (x) is about 22 mm, so that the longitudinal direction (y). Is also designed to be equal to the lateral dimension.

With such design values, the main lens diameter of the main electrode 2 is 19 in the lateral direction (A) as shown in FIG.
The diameter (B) in the vertical direction is about 8 mm in consideration of the installation area of the bead glass.

At this time, since the main lens of the main electrode is formed inside by the burning operation, the outer frame 2a is formed in the opening, and the width (C) of the outer frame 2a is about 1 mm in the vertical direction. Is formed.

As described above, such a main lens diameter is optimally manufactured in a circular shape, not in the elongated hole shape shown in FIG. 2, but a bead for fixing each electrode at equal intervals. From the aspect that the installation area of the glass 5 has to be taken into consideration and the aspect that the electrodes that form the main lens have to be processed at all, the oblong electrode, which is not circular, has to be adopted. It's a reality.

As a result, the main lens 2 having a long lens diameter has a horizontal diameter (A) larger than a vertical diameter (B), and therefore a voltage is applied to the main electrode 2. In this case, since the effective diameter in the horizontal direction is larger than the diameter in the vertical direction, the penetration of the electric potential becomes significant in the horizontal direction, and the lens converging force in the horizontal direction becomes weaker than that in the vertical direction. , The astigmatism until the electron beam is converged while passing through the electrode is increased.

That is, comparing the convergence point of the electron trajectory in the horizontal direction with the convergence point of the electron trajectory in the vertical direction, the convergence point of the screen becomes shorter in the vertical direction, so that the beam spot on the screen has a horizontal diameter. The diameter becomes larger than the diameter in the vertical direction, which deteriorates the resolution in the horizontal direction.

Therefore, as shown in FIGS. 1 and 2, the main electrode 2
Auxiliary electrodes 4 are provided so that three elliptical electron beam through holes 3 are formed therein, and the diameter (A) in the horizontal direction is adjusted to be smaller than the diameter (B) in the vertical direction. Thus, the astigmatism is removed by adjusting the electron beam converging force in both the horizontal and vertical directions.

[0016]

However, in such a conventional electron gun, in the large-diameter main electrode 2, the ratio point due to the difference between the horizontal diameter (A) and the vertical diameter (B) is large. In order to reduce the aberration, a separate auxiliary electrode 4 is provided in the main electrode 2 so that an elliptical electron beam through hole 3 having a vertical diameter (B) larger than a horizontal diameter (A) is formed. Since it is necessary to reduce the productivity, of course, during the assembly process of the electron gun, the circular electron beam through hole was used as a reference to determine the position and assemble it. Beam through hole 3
Due to the presence of the mixture, the assembly precision was deteriorated due to the minute deformation of the auxiliary electrode 4.

In particular, since the auxiliary electrode 4 is provided immediately after the vertically elongated elliptical electron beam through hole 3 is formed in the main electrode 2, the auxiliary electrode 4 is easily deformed, whereby the focusing characteristics are improved. There was a problem of deterioration.

The object of the present invention is to eliminate the above-mentioned conventional problems, and to mainly deal with astigmatism caused by a large difference between the horizontal diameter and the vertical diameter of the main electrode. It is to increase the diameter of the electrode in the vertical direction so that astigmatism can be eliminated.

[0019]

According to the first feature of the present invention for achieving the above object, an electrode having three electron beam through holes integrally formed therein and fixed to a screen surface of this electrode. There is provided a focus electrode structure of an electron gun for a color cathode ray tube, which includes a main lens electrode having a vertical diameter in which upper and lower parts are curved.

According to a second aspect of the present invention, the first
The main lens electrode having the above characteristics is expanded and laminated in a tube expanding plate or in multiple stages to expand the diameter of the main electrode lens in the vertical direction.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a detailed description with reference to FIG. 3 attached to one embodiment of the present invention.

FIG. 3 is a front view showing a main part of a main electrode according to an embodiment of the present invention and a longitudinal sectional view thereof, and in the present invention, three electron beam through holes 7 are integrally formed in an electrode 6. Then, the main lens electrode (8) having a vertical diameter (B ') whose upper and lower parts are curved is connected to the front surface of the electrode 6.
Fix it.

Compared with the conventional structure shown in FIG. 2b, this removes the outer frame (2a) caused by the burning operation of the main electrode, and further increases the vertical diameter of the main electrode by about 2 mm. It is designed so that it can be enlarged.

Here, the number of about 2 mm is weak, but the performance improvement with the increase of this size is remarkable, and the size of this increase is such that the diameter of the neck portion of the electron gun is larger. It will be expanded.

Thus, conventionally, the diameter (B) of the main lens electrode in the vertical direction is about 4 times the diameter (A) in the horizontal direction.
Although it is formed to have a size of about 2%, in the present invention, the vertical diameter (B ') is 47% or more of the horizontal diameter (A). Is formed.

Further, in one embodiment of the present invention, the state where the main lens electrode 8 as shown in FIG. 3 is fixed to one of the electrodes 6 has been described, but as shown in FIG. 4a shown in another embodiment. In addition, the main lens electrode 8 may be laminated in multiple stages on one of the electrodes 6 so that the opening gradually becomes larger, or formed by a plate so that the opening is gradually expanded as shown in FIG. 4b. This increases the vertical diameter of the main electrode.

[0027]

As described above, according to the present invention, while the electrode 8 is in contact with the electrode 6, a separate main lens electrode 8 having a vertical diameter (B ') on one side larger than the conventional vertical diameter is provided. Since it is provided, the productivity can be improved by the ease of the assembly process, and the main lens electric field strength can be expanded to the screen surface side while spatially configuring it, so the focus is more remarkable than that of conventional electron guns. The effect that the characteristics can be obtained is obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a neck portion of a conventional CRT.

FIG. 2a is a front view of a conventional focusing electrode. FIG. 2b is a vertical cross-sectional view of a conventional focusing electrode.

FIG. 3a is a front view showing a main part of a focusing electrode according to an embodiment of the present invention. FIG. 3b is a front view showing the main part of the main electrode according to one embodiment of the present invention.

FIG. 4a is a vertical cross-sectional view showing another embodiment of the present invention. FIG. 4b is a vertical sectional view showing still another embodiment of the present invention.

[Explanation of symbols]

 2a Outer frame 7 Electron beam through hole 8 Main lens electrode A Horizontal diameter B'Vertical diameter

Claims (4)

[Claims] 1. An electrode in which three electron beam through holes are integrally formed, and a vertical diameter (B ') in which upper and lower portions are curved, and is connected and fixed to a screen surface of the electrode. A focus electrode for an electron gun for a color cathode ray tube, which is composed of a lens electrode. 2. The focus electrode for an electron gun for a color cathode ray tube according to claim 1, wherein the main lens electrode is formed in a multi-layered structure so that the opening becomes gradually larger. 3. The focus electrode for an electron gun for a color cathode ray tube according to claim 1, wherein the main lens electrode is formed of a plate having an opening gradually expanded. 4. The main lens electrode is formed so that a vertical diameter thereof is 47% or more as compared with a horizontal diameter thereof.
The focus electrode of the electron gun for a color cathode ray tube according to any one of 1.