KR19980035138A - Electron gun for color cathode ray tube - Google Patents

Abstract

The present invention relates to an electron gun for a color cathode ray tube, and in particular, the electron beam through hole shape of the first grid (G1), the second grid (G2) is configured in the longitudinal / horizontal direction to prevent distortion of spots throughout the screen. The goal is to increase the resolution across the screen.

Description

Electron gun for color cathode ray tube

1 is a conventional electron gun configuration diagram.

2 is a distortion diagram of an electron beam caused by a pincushion magnetic field.

3 is a perspective view of an essential part according to the present invention.

4 is a first grid ball shape according to the present invention.

5 is a second grid ball shape according to the present invention.

6 is a horizontal electron beam focusing speed according to the present invention.

7 is an electron beam focusing speed in the vertical direction according to the present invention.

8 is a horizontal and vertical focusing principle in the screen of the electron beam according to the present invention.

9 is a shape diagram of an electron beam on a screen according to the present invention.

10 is a cross-sectional view of a second grid of a conventional electron gun.

Explanation of symbols on the main parts of the drawings

32a, 32b, 32c: heater 50: cathode

51: first grid 52: second grid

51a, 51b, 51c: first grid electron beam passing hole

70: longitudinal electron beam 71: longitudinal electron beam

The present invention relates to an electron gun for a color cathode ray tube, and in particular, the electron beam through hole shape of the first grid (G1), the second grid (G2) is configured in the longitudinal / horizontal direction to prevent distortion of spots throughout the screen. The goal is to increase the resolution across the screen.

The electron gun of the conventional color cathode ray tube is generally formed by stacking a plurality of in-line integrated grid electrodes in which a plurality of electron beam through-holes are perforated in a long circle in an in-line on a grid electrode of a flat plate and a flat plane. The main part is constituted by fusion and fixation with bead glass while maintaining a distance between predetermined grid electrodes by the force of. As shown in FIG. 1, the plurality of grid electrodes sequentially stacked may include a first grid electrode constituting an electron beam forming region for forming hot electrons emitted from a cathode 1 having a heater 2 as an electron beam. (3) and the second grid electrode (4), the focusing electrode (5) and the second acceleration and focusing electrode (6) constituting a capacitive focusing lens for narrowly focusing and forming the subsequent incident electron beam .

In addition, depending on the type, in order to achieve a multi-focus type in which the focusing effect is enhanced, a third grid electrode and a fourth grid electrode for inserting shear are additionally inserted between the grid electrode constituting the electron beam forming region and the electrode constituting the electrostatic focusing lens. (Not shown in the figure).

In the above-described general CRT electron gun, an electron beam is formed through the first grid electrode and the second grid electrode, and the optical focus is narrowly passed through the main lens formed by the difference between the focusing electrode, the second acceleration, and the voltage applied to the focusing electrode. , It is accelerated to form a beam spot on the screen. At this time, the electron beam passing holes of all the electrodes from the first grid electrode 3 to the second acceleration and focusing electrode 6 arranged in sequence are circular near the long circle. When the electron beam arrives at the center of the screen of the color cathode ray tube unaffected by the deflection yoke, the electron beam is scanned over the entire screen by a deflection magnetic field in the deflection yoke in which the electron beam leaving the circular gun is excreted for a predetermined distance from the exit of the electron gun. To reproduce the image. The magnetic field must concentrate a plurality of electron beams at one point on the screen. For this purpose, as described above, the electron beam is emitted in a horizontal in-line from the electron gun, and the magnetic field generated by the deflection yoke is a non-uniform magnetic field. It adopts the Sharpe convergence method to achieve

The non-uniform magnetic field may be divided into a pincushion magnetic field 7 and a barrel magnetic field.

The deflection of the electron beam due to the barrel magnetic field during deflection is weak, but the distortion due to the pincushion magnetic field compresses the electron beam in the upper and lower sides because the magnetic field components applied to the respective portions of the electron beam are different as shown in FIG. Since it acts as a quadrupole component that tensions the electron beam, it is scanned through the deflection region and viewed as a whole in the electron beam spot, and at the same time, it is crushed in a horizontal shape. These electron beams have greatly reduced the resolution of the screen.

In addition, in Japanese Patent No. 63-232246, Pyeong 4-10693, a rectangular groove 17 is formed in the second grid around the electron beam through hole 16 that is circular in the third grid direction as shown in FIG. We're improving the spotlight, but we couldn't get enough of it.

This horizontal spot forms an electron beam spot consisting of a core portion 9 having a high electron beam density and a halo portion 10 having a low electron beam density. This is because the intensity of the non-uniform field is increased toward the periphery of the screen. Becomes more remarkable. Because of this phenomenon and the focus comfort of the electron beam and the distance from the screen to the periphery of the screen, the core (9) part becomes smaller and the halo (10) part of the electron beam spot appears on the screen toward the periphery of the color cathode ray tube. As it becomes larger, the resolution of the screen is greatly reduced.

The present invention has been made to solve the above problems, which is particularly intended to provide an electron gun for a color cathode ray tube which has improved the electron beam spot characteristics of the periphery and the center of the screen of the color cathode ray tube to have a uniform spot on the front of the screen. will be.

3 is a perspective view showing a specific electrode configuration of the present invention.

The cathodes 31a, 31b, and 31c for emitting electron beams and the heaters 32a, 32b, and 32c are accommodated therein, and the first grid 51, the second grid 52, and the third grid electrode (sequentially) 53).

The shape of the electron beam through holes 51a, 51b, 51c of the first grid electrode 51 has the shape of an electron beam through hole in a rectangular shape having a long vertical direction (Y-Y ') as shown in FIG. The size V in the vertical direction of the electron beam is 1.1 to 1.4 times larger than the size H in the horizontal direction, and the shape of the electron beam through holes 52a, 52b, and 52c of the second grid electrode 52 is As shown in FIG. 5, the horizontal direction X-X 'has a long rectangular shape.

The end portions of the electron beam through holes 51a, 51b and 51c of the first grid electrode 51 and the electron beam through holes 52a, 52b and 52c of the second grid electrode 52 are 4 and 5 degrees. As shown in the figure has a semi-circular shape for ease of manufacture.

Reference numeral 50 denotes a cathode, 70 denotes a horizontal electron beam, and 71 denotes an elongated electron beam.

The present invention configured as described above has a structure designed to minimize the distortion of the electron beam when deflecting to the periphery of the screen of the electron beam. When the electron beam is incident on the main lens, the electron beam is formed into a horizontal shape 70 to deflect aberration in the deflection region. By minimizing the halo in the peripheral electron beam spot of the screen, the resolution is improved over the entire screen area. The principle of forming the horizontally-shaped electron beam according to the present invention is that the focusing action of the electron beams in the vertical direction and the horizontal direction varies depending on the shape of the ball as shown in the electron beam focusing speeds of FIGS. 6 and 7.

That is, in the vertical direction (FIG. 7), since the electron beam through holes 51a, 51b, 51c of the first grid electrode 51 have a large diameter, the crossover 16 is formed farther from the cathode surface, and the divergence angle (α) ') And the horizontal grid (X-X') of the second grid helps the prefocus lens to focus the electron beam even more in the vertical direction.

In contrast, as shown in FIG. 6, in the horizontal direction, the size of the electron beam through holes 51a, 51b, 51c, 52a, 52b, 52c of the electron beams of the first grid 51 and the second grid 52 is vertical. Since the focusing of the electron beam is reversed, the divergence angle α becomes larger than the vertical direction, so that the shape of the electron beam incident on the main lens as shown in FIG.

When the vertical direction V of the electron beam passing hole of the first grid electrode 51 according to the present invention is 1.1 times or less than the horizontal direction, the focusing effect of the electron lens is small, and when the size is 1.4 times or more, the focusing effect of the electron lens is The maximum area or the emission area of the electron beam is increased, and the electron beam collides in the first grid.

As shown in FIG. 2, the lengthened electron beam is deflected in the vertical direction because the size of the electron beam in the vertical direction is smaller than the horizontal direction as in the degree of distortion of the electron beam by the PIN-CUSHION magnetic field 7. The aberration becomes small.

In fact, because the pincushion magnetic field 7 becomes stronger at the periphery of the screen, the electron gun according to the present invention shows a slight longitudinal electron beam 71 spot (Fig. 8) and a periphery of the screen at the center of the screen as shown in FIG. The electron beam without the halo portion 10 can be obtained to increase the resolution of the color CRT.

Since the electron gun for the color cathode ray tube according to the present invention is only a core portion having a high electron beam density to the center portion as well as the periphery of the screen, the CRT employing the electron gun according to the present invention can obtain high resolution to the center portion as well as the periphery portion. The effect can be obtained.

In addition, the first grid and the second grid electrode according to the present invention are easier to process than other types of electrodes.

Claims (2)

In the in-line type color cathode ray tube consisting of the cathode, the first grid, the second grid, the third grid, the fourth grid sequentially arranged in the screen direction, The shape of the electron beam through hole of the first grid is composed of a square hole having a vertical direction and semicircles at both ends, and the shape of the electron beam through hole of the second grid is a square cathode tube having a long horizontal direction and a semi circle at both ends. Electron gun sphere. The method of claim 1, An electron gun sphere for a color cathode ray tube having a ball shape in which the size (V) in the vertical direction of the first grid is 1.1-1.4 times the size (H) in the horizontal direction.