KR100316106B1 - Electronic Gun of In-line type for CRT - Google Patents

Abstract

The present invention provides a three-pole portion comprising a control electrode and an acceleration electrode for controlling and accelerating the amount of each electron beam emitted from a plurality of cathodes, an electrode acting as a shear-focusing lens by focusing the three electron beams by a predetermined amount, and the three electron beams. In an electron gun in which a focusing electrode and an anode electrode serving as a main lens for focusing on a screen are provided in a neck, the focusing electrode serving as the main lens and to which a dynamic voltage is applied, has a horizontal width of a common opening through which the three electron beams pass. When h is the horizontal outer width of the electrode, the ratio h / w is 0.89 or more, and the distance from the anode electrode is 1.0 mm or less. 6 Reduce the gap between the electrodes and change the dimensions of the electrodes slightly to minimize the electrostatic STC drift that hinders the progress of the electron beam. It provides an in-line electron gun of a cathode ray tube that can be implemented.

Description

Electronic Gun of In-line Type for CRT

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun for a color cathode ray tube. In particular, a main lens is formed by a potential difference between two electrodes generated due to different applied voltages. The present invention relates to an in-line electron gun of a cathode ray tube that can improve the electrostatic STC drift phenomenon occurring during neck charge.

1 is a cross-sectional view showing a schematic configuration of a general color cathode ray tube, a panel 1, a fluorescent surface 2 coated with red, green and blue phosphors on an inner surface of the panel, and a shadow mask 3 having a color sorting function. And a funnel 4 which is coupled to the side surface and has a tubular neck portion 5 formed rearward.

An electron gun 10 is embedded inside the neck portion 5 extending from the funnel 4, and a deflection yoke 7 for deflecting the electron beam emitted from the electron gun in a horizontal direction or a vertical direction is coupled thereto.

The conventional electron gun configured as described above is composed of a triode and a main lens as shown in FIG. 2, wherein the three pole includes a cathode 18 having a heater 19 therein and arranged in-line, and radiating heat from the cathode 18. It consists of a control electrode 11 and an acceleration electrode 12 for controlling and accelerating the hot electrons, and the main lens unit is composed of a focusing electrode 13 and an anode 14 for focusing and finally accelerating the electron beam generated in the triode. .

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

In the conventional color image tube electron gun configured as described above, as a predetermined voltage is applied to each electrode, an electrostatic lens is formed by a potential difference between the focusing electrode 13 and the anode 14 and is generated in the triodes 11 and 12. The electron beam is focused to the center of the fluorescent surface.

At this time, the deflection yoke 7 attached to the funnel 4 acts to deflect the electron beam focused at the center of the fluorescent screen to the entire area of the screen. In a cathode ray tube using an in-line electron gun, the deflection yoke 7 is normally used. Since three electron beams, green and blue, are arranged side by side horizontally, the deflection yoke (7) applies a self-convergence using a non-uniform magnetic field in order to converge the three electron beams in one place of the fluorescent surface. .

The focusing electrode 13 and the anode electrode 14 are main lens forming electrodes, and a shield cup 15, which is a shielding electrode for shielding and weakening the leakage magnetic field of the deflection yoke 7, is formed at the electrode farthest from the cathode. have.

In general, the size of the electron beam pixel is due to the influence of spherical aberration, and when the spherical aberration is large due to this effect, the electron beam deteriorates the sharpness by degrading the resolution. The periphery, the deflection zone, works the same.

Such spherical aberration is inversely proportional to the third power of the main focusing electrostatic lens aperture R, as can be seen by the following equation, and the aperture R of the main focusing lens has a diameter equal to that of the focusing electrode and the final accelerating electrode. Almost proportional. The lens between the focusing and the final accelerating electrode is called the main lens, and as the diameter of the main lens increases, the focusing intensity decreases, and the pixels form an image in front of the screen and the focusing voltage decreases. In order to maintain the same focusing voltage, the length of the electron gun may be increased to achieve the same focusing intensity. As the diameter of the main lens increases, the size of the pixel may decrease and the sharpness may be improved.

Thus, the size Ds of the final image on the screen is expressed by Equation 1 below.

Dx is the magnification of the main lens, Dsa is spherical aberration, and Dsc is the electron beam expanding component due to the space charge repulsion effect.

Therefore, when the space charge repulsion effect is increased, the pixel is enlarged by the repulsive force, and when the electron beam radius is increased to suppress the repulsion effect, spherical aberration increases, and thus, the optimum condition must be found.

In this way, if the diameter of the main lens is increased to reduce spherical aberration, the divergence angle can be increased, so that the size of the pixel can be further reduced, and the image quality can be obtained.

Many attempts have been made to implement a large-diameter electron gun. For example, the shape of the electrostatic shielding electrode (not shown) of the main lens is formed in an oval shape, and the position of the electrostatic shielding electrode is made deeper on the opposing surface of the main lens. The method of constructing etc. was developed.

Another method is to change the shape of the main lens somewhat to increase the horizontal size by 3 to 5% compared to the conventional and to increase the vertical aperture by 15 to 20% compared to the conventional activities to promote the large diameter.

As described above, when the diameter of the main lens is increased by reducing the spherical aberration, electrostatic STC drift does not occur due to neck charge, but the horizontal size of the main lens is increased by 3 to 5% compared to the conventional one, and the vertical aperture is increased. When the large diameter is implemented by increasing the 15 to 20% compared to the conventional will cause the STC drift.

The electrostatic STC drift is applied to the anode voltage forming the main lens from the embedded graphite 17 of the neck 5 as shown in FIG. 3A, and the anode voltage is applied to the shield cup 15 to form the main lens. At the same time, the electron beam is accelerated to form an electron beam on the screen.

However, this anode voltage flows down the neck 5 side, and this voltage is called the neck charging voltage i, and this voltage is considerably higher than the electrode voltage ii as shown in FIG. The electrode voltage (ii) causes the largest change between the fifth electrode 13 and the sixth electrode 14 forming the main lens, and the neck charge voltage i higher than the electrode voltage (ii) is zero. It penetrates between the fifth electrode 13 and the sixth electrode 14 and thereby acts in a direction that obstructs the path of the side electron beams R and B passing through the main lens.

As shown in FIG. 4, the electron beam is attracted to the neck charging voltage i so that the electron beam is attracted to the neck direction. This phenomenon does not coincide with the supply of power, but depends on the time for which the voltage is charged to the neck.

In addition, as shown in FIG. 4, the change amount becomes maximum in about 3 to 24 hours, and the change amount is about 0.1 to 0.2 mm at the maximum. This phenomenon occurs mainly when the main lens is to be formed with a large diameter, and it is a major cause of deterioration of image quality.

Accordingly, the present invention improves image quality by minimizing the electrostatic STC drift caused during neck charge by changing the dimensions of the fifth and sixth electrodes serving as the main lens to an optimal state. To provide an in-line electron gun of a cathode ray tube.

Technical means of the present invention for achieving the above object, a triode portion consisting of a control electrode and an acceleration electrode for controlling and accelerating the amount of each electron beam emitted from a plurality of cathodes, and focusing the three electron beams by a predetermined amount to shear focusing lens In the electron gun provided in the neck, an electrode serving as a main lens and a focusing electrode serving as a main lens for focusing the three electron beams on a screen, the focusing electrode serving as the main lens and to which a dynamic voltage is applied, When the horizontal width of the common opening through which the electron beam passes is h, and the horizontal outer width of the electrode is w, the ratio of h / w is 0.89 or more, and the distance from the anode electrode is 1.0 mm or less. It is done.

1 is a cross-sectional view showing a schematic configuration of a general color cathode ray tube,

2 is a view showing the structure of an electron gun according to the prior art,

FIG. 3 is a diagram for describing an electrostatic STC drift phenomenon caused by the fifth and sixth electrodes of FIG. 2. FIG. 3A illustrates an electrode structure, and FIG. 3B illustrates a fifth electrode and an STC drift voltage. It's a graph,

4 is a view for explaining the STC drift phenomenon of FIG.

5 is a view for explaining the structure and design dimensions of the fifth electrode and the sixth electrode of the electron gun according to an embodiment of the present invention,

6 is a view for explaining the electrode dimensions of FIG.

FIG. 7 is a diagram illustrating an STC drift value according to the electrode dimension of FIG. 6, FIG. 7A is an STC drift value according to the electrode dimension (h / w), and FIG. 7B is a gap between the fifth electrode and the sixth electrode. This shows the STC drift value.

Explanation of symbols on the main parts of the drawings

5: Neck 13, 14: main lens

13: fifth electrode 14: sixth electrode (anode electrode)

15: Shield Cup

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

FIG. 5 is a view illustrating a structure of an electron gun for improving an electrostatic STC drift according to an embodiment of the present invention, and illustrates a fifth electrode 13, a sixth electrode 14, and a neck 5.

The present invention relates to a design specification between the fifth electrode 13, the sixth electrode 14 and the neck 5, and the distance (g) between the electrodes 13, 14 and the neck 5 as shown in the figure. The larger the value and the larger the bridge width a of each electrode, the smaller the distance d between the fifth electrode 13 and the sixth electrode 14 decreases, so that the electrostatic STC drift decreases. On the other hand, the farther the distance between the main lens and the screen (L; not shown), the greater the electrostatic STC drift.

Therefore, the electrostatic STC drift (STCd) has a correlation as shown in Equation 2 below.

Provided that d is an interval between the fifth electrode 13 and the sixth electrode 14, g is an interval between the electrodes 13, 14 and the neck 5, a is the bridge width of each electrode, and L Is the distance between the main lens and the screen.

In the conventional case, g is 1.1 mm, a is 1.2 mm, d is standardized to 1.0 mm, and in particular, d is used by most manufacturers with 1.0 mm.

In the present invention, in order to form a large diameter, as shown in FIG. 6, the horizontal size (h) of the main lens was extended by about 3 to 5%, and the outer width (w) was extended by about 2%. In this configuration, the electrostatic STC drift acted in a decreasing direction compared to the conventional electron gun.

In order to improve the electrostatic STC drift as described above based on the ratio of h / w, as shown in Figure 7a, when measuring the electrostatic STC drift while increasing the ratio of h / w, y = -0.08x + It can be seen that it has a correlation of 7.26.

In other words, as the ratio of h / w increases, the electrostatic STC drift increases, and the gap between each electrode needs to be reduced in order to improve it. If the gap is excessively reduced, the electron beam is not controlled by the desired path (Stray Emission). There is a risk of occurrence and should be reduced with caution.

In FIG. 7B, when the interval in which the electrostatic STC drift does not occur according to the ratio of h / w is derived, it can be seen that the correlation is y = 0.05x + 5.44.

As the ratio of h / w increases, the distance d between the fifth electrode 13 and the sixth electrode 14 must be reduced.

Therefore, in the present invention, when the dimension of the horizontal diameter of the main lens is referred to as h and the electrode outer width is referred to as w to promote the large diameter, the fifth electrode 13 and the case where the ratio of h / w × 100 is 89% or more. It can be seen that the distance between the sixth electrodes 14 should be managed to 1.0 mm or less.

Therefore, in the present invention, by reducing the distance between the fifth electrode and the sixth electrode acting as the main lens, and slightly changing the dimensions of the electrode, the electrostatic STC drift that interferes with the progress of the electron beam can be minimized to achieve better image quality. It can be effective.

Claims (1)

A triode comprising a control electrode and an acceleration electrode for controlling and accelerating the amount of each electron beam emitted from a plurality of cathodes, an electrode acting as a shear focusing lens by focusing the three electron beams by a predetermined amount, and focusing the three electron beams on the screen. In the electron gun provided in the neck, the focusing electrode and the anode electrode acting as a main lens A focusing electrode acting as the main lens and to which a dynamic voltage is applied, When the horizontal width of the common opening through which the three electron beams pass is referred to as h, and the horizontal outer width of the electrode as w, the ratio of h / w is 0.89 or more, and the distance from the anode electrode is 1.0 mm or less. In-line electron gun of the cathode ray tube, characterized in that.