KR200156561Y1 - 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, an object thereof is to prevent resolution deterioration at the periphery of a screen by forming an optimal size of a pixel forming an image on a screen.

In order to achieve the above object, the present invention focuses on a three-pole portion comprising a cathode having a heater for cathodic heating, a control electrode and an acceleration electrode for controlling and accelerating hot electrons radiated from the cathode, and an electron beam generated from the three-pole portion. In the electron gun for a color cathode ray tube provided with a main lens portion consisting of a focusing electrode and an anode for accelerating, a concave electrode facing surface of the acceleration electrode is formed with a wide groove in the horizontal direction and a narrow groove in the vertical direction, the inside of the groove portion An electron beam through hole is formed, and the vertical width of the groove portion is 1.4 times to 2.0 times the pore diameter.

Description

Electron gun for color cathode ray tube

The present invention relates to an electron gun for a color cathode ray tube, and more particularly, to an electron gun for a color cathode ray tube to prevent resolution deterioration at the periphery of a screen by forming an optimal size of a pixel forming an image on a screen.

As shown in FIG. 1, a general color cathode ray tube is fused to a panel 2 having R, G, and B fluorescent films 1 coated on its inner surface, and fused to a rear end of the panel 2 to vacuum the inside thereof. The funnel 3 to be kept in the state, the electron gun 6 inserted into the neck portion 4 of the funnel 3 to emit the electron beam 5, and the electron beam 5 emitted from the electron gun 6 A deflection yoke (7) for deflecting in the horizontal and vertical directions, and a shadow mask (8) in which a plurality of openings are formed so that color discrimination occurs while the electron beam (5) deflected by the deflection yoke (7) passes.

As shown in FIG. 2, the electron gun 6 includes a triode and a main lens unit. The tripole includes a heater 9 for cathodic heating and generates heat from the heater 9 when the heater 9 generates heat. A cathode 10 for receiving the hot electrons, a control electrode 11 for controlling the hot electrons emitted from the cathode 10, and an acceleration electrode 12 for accelerating the hot electrons passing through the control electrode 11. The main lens unit comprises a focusing electrode 13 and an anode 14 for focusing and finally accelerating the electron beam 5 generated in the triode.

Here, the voltages applied to the electrodes are grounded to the control electrode 11, a high voltage of 500 to 1000 V is applied to the acceleration electrode 12, and 25 kV to 35 kV is applied to the anode 14, and the focusing electrode 13 is applied. An intermediate voltage of 20 to 30% of the voltage applied to the anode 14 is applied.

When power is applied to the conventional color cathode ray tube configured as described above, the electron beam 5 is radiated from the electron gun 6, and the electron beam 5 is deflected by the deflection yoke 7 and passes through the shadow mask 8. The image is reproduced by hitting the fluorescent film 1 in the state of color selection.

The electron gun 6 radiating the electron beam 5 has a voltage difference between the focusing electrode 13 and the anode 14 as the above-described predetermined potential is applied to each of the electrodes 11, 12, 13, and 14. An electrostatic lens (main lens) is formed so that the electron beam 5 generated at the triodes 9, 10, 11, 12 is focused at the center of the fluorescent surface 1.

At this time, in order to deflect the electron beam 5 focused at the center of the fluorescent surface 1 to the entire screen area, the action of the deflection yoke 7 is required. In general, a color using an in-line electron gun In the case of the cathode ray tube, the red, green, and blue three-color electron beams 5R, 5G, and 5B are arranged in a horizontal direction, so that the three-color electron beams 5R, 5G, and 5B converge to one of the fluorescent surfaces 1. Self-convergence deflection yoke that allows tricolor electron beams 5R, 5G, 5B to achieve convergence on the screen without the use of additional circuits and additional devices. 7) is applied.

Distribution of the magnetic field generated in the deflection yoke 7 to which the self-focus type is applied is as shown in (a) and (b) of FIG. 3, and the horizontal and vertical deflection magnetic fields are made into barrel or pin-cushion type magnetic fields for each part. The three-color electron beams 5R, 5G, 5B have different deflection forces depending on the position, so that electron beams 5R, 5G, 5B of different distances from the starting point to the screen of the arrival point are collected at the same point. To help.

However, as shown in (c) and (d) of FIG. 3, the magnetic field can be described by dividing it into a dipole component and a quadrupole component. The dipole component serves to deflect the electron beam 5 in the horizontal and vertical directions. Since the four-pole component serves to focus the electron beam 5 in the vertical direction and diverge it in the horizontal direction, astigmatism is generated to distort the spot of the electron beam 5, even though the magnetic field is close to uniformity. Even if the fine pincushion or barrel magnetic field component causes the electron beam 5 to be remarkably astigmatized at the periphery of the fluorescent surface 1, the beam spot is distorted.

4A and 4B illustrate such a problem in detail, and since the deflection magnetic field is not applied at the center of the screen, the spot of the electron beam 5 has an accurate shape, but at its periphery, it is divergent in the horizontal direction and in the vertical direction. As a result, overdense and distorted high-density crosswise cores 15 and hazes 16, which are low density up-and-down phenomena, are generated above and below, resulting in resolution degradation at the periphery of the screen. This problem becomes larger as the screen is larger and the deflection angle becomes larger.

However, this phenomenon is caused by a large amount of deflection aberration at the center of the deflection yoke, and the horizontal direction from the deflection center of the electron beam is offset by the divergence of the deflection magnetic field and the focusing force due to the distance difference. In the vertical direction, a high density horizontal core is distorted by overlapping the focusing force due to deflection aberration and the focusing force due to a distance difference, and a haze that is a low density upper and lower spreading phenomenon. ), And this haze has a problem of deteriorating the peripheral resolution of the screen.

In order to solve this problem, generally, an asymmetric tripolar portion may be formed. To this end, as shown in FIG. 5, a wide horizontal direction is formed in the acceleration electrode 12 and a narrow groove portion 17 is formed in the vertical direction, and the groove portion 17 is formed. ) The thickness of the forming surface is 0.4 to 1.0 times the pore diameter, and the thickness of the portion where the groove portion 17 is formed is 0.1 to 0.2 times the pore diameter (US Pat. No. 4,886,998) so as to deflect the electron beam generated at the triode as much as possible. In order to improve the haze component at the periphery by making the electron beam receive less deflection aberration at the center, the spherical aberration is so large that the spherical aberration is largely received in the main lens. There is a problem that is increased, thereby causing a resolution degradation.

The present invention is designed to make the size of the pixel optimal in view of the above. A long groove in the horizontal direction and a narrow groove in the vertical direction are formed on the converging electrode facing surface of the acceleration electrode. An electron beam through hole is formed, and the vertical width of the groove portion is 1.4 times to 2.0 times the pore diameter, thereby reducing the horizontal size of the pixel and increasing the vertical size to improve the resolution and moire characteristics of the cathode ray tube. The purpose is.

1 is a block diagram of a general color cathode ray tube.

2 is a configuration diagram of an electron gun for a conventional color cathode ray tube.

3 is an electron beam deflection characteristic diagram of a conventional color cathode ray tube;

(A) is a state diagram showing vertical deflection.

(B) is a state diagram showing horizontal deflection.

(C) and (D) are deflection characteristic diagrams of bipolar and quadrupole components.

FIG. 4 illustrates distortion of an electron beam spot formed on a screen of a conventional color cathode ray tube.

A state diagram.

(B) is also operation.

5 is an acceleration electrode of a conventional electron gun for color cathode ray tubes,

(A) The top view.

(B) section.

6 is a block diagram of the electron gun for the present invention color cathode ray tube.

7 shows an acceleration electrode of an electron gun for a color cathode ray tube of the present invention,

(A) The top view.

(B) section.

8 is an experimental view for the present invention,

(A) is a graph showing the size of the pixel according to the change of the horizontal width.

(B) is a graph showing the size of pixel according to the change of vertical width.

(C) is a graph showing the size of the pixel according to the change in the vertical width when the groove depth is 0.1 times the pore diameter.

*** Explanation of symbols for the main parts of the drawing ***

101 heater 102 cathode

103 control electrode 104 acceleration electrode

105: focusing electrode 106: anode

107: groove 108: electron beam through hole

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 6 is a schematic view of an electron gun according to the present invention, and includes a three pole portion and a main lenb portion, wherein the three pole portion includes a cathode 102 having a heater 101 for cathode heating, and radiation from the cathode 102. And a control electrode 103 and an acceleration electrode 104 for controlling and accelerating the hot electrons, wherein the main lens part includes a focusing electrode 105 and an anode 106 for focusing and finally accelerating the electron beam generated from the triode. It is composed.

As shown in FIG. 7, the accelerating electrode 104 has a wide groove in the horizontal direction and a narrow groove 107 in the vertical direction on the opposite surface of the focusing electrode 105, and an electron beam inside the groove 107. A through hole 108 is formed, and the vertical width of the groove portion 107 is configured to be 1.4 times to 2.0 times the pore diameter.

The basis of such a configuration has been found through experiments as shown in FIG. 8. First, the thickness of the groove 107 forming surface of the acceleration electrode 104 (that is, the thickness around the ball) is 0.8 times the pore diameter, and the groove 107 is formed. The thickness of the formed part is set to 0.1 times the pore diameter to attempt the first optimal design in which the electron beam is optimally incident on the main lens. Up to 3.5 times, the vertical width was changed from 1.2 times to 2.2 times the pore size, and the size of the pixels on the screen was examined.

As shown in (a) and (b) of FIG. 8 through this experiment, the size of the pixel is not sensitive to the horizontal width of the groove 107, and is closely related to the vertical width of the groove 107. Turned out.

This means that the pixel size is almost unchanged until the vertical width is 1.4 times the pore size. When the vertical width is 1.4 times or more, the horizontal size of the pixel decreases and the vertical size increases in the center of the screen. It can be seen that the elongation from the long form to the long form.

However, as the vertical width increases, the vertical size of the pixels in the periphery increases gradually, which is caused by the deflection aberration of the deflection yoke, and it can also be seen that the deflection aberration increases as the vertical width increases.

In this case, the size of the pixel in the center of the screen represents the size of the minimum pixel when the focusing voltage is optimal, and the size of the pixel in the peripheral portion is data when the predetermined fixed focusing voltage is applied. This is to more accurately determine the influence of the deflection yoke.

The change of the electron beam from the horizontal to the longitudinal type means that the horizontal size decreases and the vertical size increases, so that the resolution of the screen can be improved as the horizontal size decreases, and as the vertical size increases, the moiré characteristics of the screen ( The moiré characteristic means that a wave pattern appears on the screen due to interference between the scanning line, the color masking mask, and the electron beam pixel.).

In the primary design, the thickness of the groove 107 forming surface of the acceleration electrode 104 is 0.8 times the pore diameter, and the thickness of the portion where the groove 107 is formed is 0.1 times the pore diameter, so the depth of the groove 107 is 0.7 of the pore diameter. In the second design, the depth of the groove portion 107 is 0.1 times, and the size change of the pixel is examined while changing the vertical width.

8 (c) is a graph shown through the above experiment. As can be seen from this, when the horizontal width is three times the pore size and the vertical width is 1.2 times the pore size, the depth of the groove 107 is reduced. As the size of the pixel increases, the horizontal becomes smaller and the vertical becomes smaller, so the aspect ratio increases. If the vertical width is gradually increased, the size of the horizontal pixel decreases and the vertical size increases, similar to the primary design. .

Here, the size of the pixel in the periphery of the screen can be seen to increase significantly when the depth of the groove 107 is low. This means that when the depth of the groove 107 is low, the electron beam is more affected by deflection aberration.

Recently, in order to improve the haze phenomenon of the peripheral part, the focusing electrode is divided into two, a fixed focusing voltage is applied to the first focusing electrode, and a dynamic voltage synchronized with deflection to the second focusing electrode is applied. Therefore, even when the depth of the groove 107 of the acceleration electrode 104 is low, the applicability is high.

On the basis of the above experiment, a wide groove in the horizontal direction and a narrow groove in the vertical direction are formed on the opposing surface of the focusing electrode 105 of the acceleration electrode 104 of the electron gun, and the electron beam is formed inside the groove 107. If the through hole 108 is formed and the vertical width of the groove 107 is 1.4 to 2.0 times the pore size, the size of the pixel is decreased in the horizontal direction and increases in the vertical direction, and the size thereof is optimal. In this state, the resolution of the periphery of the screen can be improved, and the moire characteristics can be improved.

As described above, the present invention provides a wide groove in the horizontal direction and a narrow groove in the vertical direction, an electron beam passing hole is formed in the groove portion, and the groove portion is perpendicular to the focusing electrode facing surface of the acceleration electrode of the electron gun. By configuring the width so that it is 1.4 times to 2.0 times the pore diameter, the pixel size becomes optimal, which improves the resolution of the periphery of the screen.

It is effective to improve Areh characteristics.

Claims (1)

A cathode comprising a cathode having a heater for heating the cathode, a control electrode and an acceleration electrode for controlling and accelerating hot electrons emitted from the cathode, and a focusing electrode and an anode for focusing and finally accelerating the electron beam generated from the three poles. In the electron gun for color cathode ray tube provided with the main lens, On the opposite surface of the focusing electrode of the acceleration electrode, a wide groove in a horizontal direction and a narrow groove in a vertical direction are formed. An electron beam through hole is formed in the groove, An electron gun for a color cathode ray tube, characterized in that the vertical width of the groove portion is 1.4 to 2.0 times the pore diameter.