KR200228839Y1 - Electron gun for color cathode ray tube - Google Patents

Abstract

According to the present invention, the cathode (K _R , K _G , K _B ) and the cathode A control electrode G ₁ for controlling the amount of electrons generated in the cathodes K _R , K _G and K _B ; A screen electrode G ₂ for forming an electron beam by electrons generated from the cathodes K _R , K _G and K _B ; So that by focusing and accelerating the electron beams landing on the fluorescent surface can be in a color cathode-ray tubes the electron gun having at least the focusing electrode _{(G 3-1, G 3-2, G} 4), said screen electrode (G ₂₎ and the the cathode electrode from the focusing-beam passing holes (H) formed in, the plane (P) of the focusing electrode (G _3-1) so as to raise the dislocation density of the pre-focus lens formed between the (G _3-1) ( And a rim electrode (31, 41) extending a predetermined length in a direction opposite to the direction of the optical axis (K _R , K _G , K _B ). In the electron gun for a color cathode ray tube according to the present invention, a cylindrical rim electrode 31 or a cylindrical rim electrode 31 having an inclined ridge shape formed at an end thereof, or a cylindrical rim electrode 41 having an inclined ridge shape formed at an end thereof, The effect of enhancing the prefocus lens formed between the screen electrode G ₂ and the focusing electrode G _{3-1 '} can be obtained by providing the connection electrode G _3-1' .

Description

Color cathode ray optical gun

FIGS. 1 and 2 are cross-sectional views schematically showing electrodes of an electron gun for a color cathode ray tube according to a related art; FIG.

FIG. 3 is a sectional view schematically showing an embodiment of an electron gun for a color cathode ray tube according to the present invention; FIG.

FIG. 4 is a cross-sectional view schematically showing another embodiment of an electron gun for a color cathode ray tube according to the present invention; FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

K _R , K _G , K _B : cathode G 1: control electrode

G2: Stryn electrode _{G 3-1, G 3-2, G 4} : focusing electrode

P: focusing electrode plane H: beam passing hole

31, 41: Rim electrode

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 in which focus of a focus is enhanced by reinforcing a pre-focus lens portion.

There are various factors for determining the resolution of the cathode ray tube, and the most significant factor is that the electron beam emitted from the electron gun is irradiated by the red, green, and blue phosphors formed on the screen surface, spot size. The size of the beam spot can usually form the spot of the smallest diameter when the electron beam has the optimum focus, and thus the best resolution can be obtained.

In order to achieve the optimum focus in the electron gun, it is necessary to improve the so-called astigmatism and spherical aberration. For example, in order to prevent deterioration of image quality due to astigmatism, the beam is intentionally distorted in the electron gun to reach the screen, and mainly a pre-focus lens system is formed So that the electron beam passing through it is subjected to different divergent forces and convergence forces longitudinally and laterally. In order to improve the spherical aberration in the main lens system, it is preferable that the electron beam passes through the center of the main lens as much as possible. For example, when the electron beam passage hole of the main focus electrode and the final acceleration electrode is viewed from the end face of the electrode, a method of forming the rim electrode so as to have a concave shape from the main plane can be used. The spherical aberration enhancement method of the above-described method can achieve the same effect as that of the multiple low magnification main lenses superimposed. In addition, various attempts have been made in the art to improve spherical aberration and astigmatism.

1 and 2 are cross-sectional views schematically showing an electron gun according to the prior art. The electron gun 10 shown in FIG. 1 includes cathodes K _R , K _G , and K _B that emit electrons to generate electron beams of red, green, and blue, respectively, and controls for controlling the amount of electrons generated in the cathode electrode (G ₁₎ and a screen electrode for the cathode forming the electron beam as the electrons generated in (G ₂₎ and a plurality of focusing electrodes to focus and accelerate the electron beams landing on the fluorescent surface (G _3-1, G _3-2 , G4). This configuration is similar to the electron gun 20 shown in FIG.

In the electron gun having such a configuration, a prefocus lens is formed between the screen electrode G ₂ and the focusing electrode G _3-1 to preliminarily focus and diverge the electron beam, and the focus electrode G _3-2 and the focus electrode G ₄ ), And finally focuses the electron beam, thereby focusing the electron beam on the screen surface. At this time, the convergence state is adjusted by the difference in voltage applied to each focusing lens and the shape of the electrode.

In the conventional electron guns 10 and 20 shown in FIG. 1 and FIG. 2, the focusing lens G _3-2 forming the prefocus lens is a plane type (first view) formed by only plane P, Or a convex rim electrode C toward the cathode K (FIG. 2). In general, in order to improve spherical aberration, it is preferable that the electron beam passes through the center of the main lens as much as possible. For this purpose, the diameter of the electron beam incident on the main lens can be reduced by strengthening the prefocus lens. However, it is very disadvantageous to enhance the magnification of the prefocus lens in the shape of the focusing lens G _3-1 shown in FIGS. 1 and 2. That is, when the focusing lens G _{3 -} 1 is in the form of a regular plane or convex toward the cathode, when the same voltage is applied, the density of the equipotential line is inevitably limited and the magnification of the prefocus lens can not be enhanced have.

It is an object of the present invention to provide an electron gun capable of enhancing the magnification of a prefocus lens.

In order to achieve the above object, according to the present invention, there is provided a display device comprising: a cathode that emits electrons to generate electron beams to be respectively landed on red, green and blue phosphors of a screen; and a control electrode A screen electrode for forming an electron beam by electrons generated in the cathode; and an electron gun for a color cathode ray tube having a minimum focusing electrode for focusing and accelerating an electron beam and landing on a fluorescent screen, A rim electrode extending from the beam passing hole formed in one of the focusing electrodes to a predetermined length in the direction opposite to the cathode is formed so as to increase the dislocation density of the prefocus lens formed between any one of the focusing electrodes A cathode ray tube (CRT) cathode ray tube.

According to another feature of the present invention, the rim electrode is formed in a cylindrical shape.

According to another feature of the present invention, the rim electrode has a cylindrical portion extending vertically from the plane of the focusing electrode toward a direction opposite to the cathode at a predetermined length, and a cylindrical portion extending in a direction And has an inclined surface.

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

FIGS. 3 and 4 show cross sections of the electron guns 30 and 40, which are embodiments of the present invention. The basic structure of the electron gun 30 is similar to the electron guns 10 and 20 shown in Figs. 1 and 2. The electron guns 30 and 40 include cathodes K _R , K _G and K _B that emit electrons so as to generate electron beams to be respectively landed on red, green and blue phosphors on the screen, A plurality of focusing electrodes G _3-1 and G ₂ for focusing and accelerating the electron beams to land on the fluorescent screen; a control electrode G ₁ for controlling the electron beam, a screen electrode G ₂ for forming an electron beam by electrons generated at the cathode, _3-2, comprises a G _4).

Referring to the third embodiment, the beam passage hole H formed in the focusing electrode G _{3 -} 1 has a cylindrical rim electrode 31. The rim electrode 31 extends vertically from the plane P of the focusing electrode G _3-1 toward the opposite direction of the cathode K.

The embodiment of claim 4 the plane rim of the focusing electrode a cylindrical electrode 41 is the focusing electrode (G _3-1) above to a predetermined length formed in the beam passing holes (H) in (G _3-1) shown in (P ) Extending perpendicularly to the direction opposite to the cathode (K) and forming a cylindrical shape, the cylindrical end has an inclined surface enlarged to have the same shape as the funnel.

In the electron gun for a color cathode ray tube according to the present invention, a cylindrical rim electrode 31 or a converging electrode G _{3 - 1 '} of a cylindrical rim electrode 41 having an inclined ridge shape formed at an end thereof is provided on the screen electrode G can be obtained ₂₎ and pre-focus effect that the lens is enhanced to be formed between the focusing electrode (G _{3-1 ').} The reinforcement of the prefocus lens can reduce the diameter of the electron beam incident on the main lens and allows the electron beam to focus only on the center of the main lens so that deterioration in image quality due to spherical aberration can be improved. Incidentally, since the electron beam is formed in a small diameter, the electron density in the beam can also be improved. The electron gun for a color cathode ray tube having the above-described focusing electrode can be applied to all focus types of BPF type, HI-BI type, or UNI-BI type.

Claims (3)

1. A cathode (K _R , K _G , K _B ) that emits electrons to generate an electron beam to be landed on the red, green and blue phosphors of the screen, respectively; A control electrode G ₁ for controlling the amount of electrons generated in the cathodes K _R , K _G and K _B ; A screen electrode G ₂ for forming an electron beam by electrons generated from the cathodes K _R , K _G and K _B ; So that by focusing and accelerating the electron beams landing on the fluorescent surface can be in a color cathode-ray tubes the electron gun having at least the focusing electrode _{(G 3-1, G 3-2, G} 4), A beam formed on the flat surface P of the focusing electrode G _3-1 so as to increase the dislocation density of the prefocus lens formed between the screen electrode G ₂ and the focusing electrode G _3-1 , And rim electrodes (31, 41) extending from the through hole (H) to a predetermined length in a direction opposite to the cathodes (K _R , K _G , K _B ). The electron gun for a color cathode-ray tube according to claim 1, wherein the rim electrode (31) is formed in a cylindrical shape. The fuel cell according to claim 1, wherein the rim electrode (41) comprises: a cylindrical portion extending vertically from a plane (P) of the focusing electrode (G _3-1 ) to a direction opposite to the cathode (K) And an inclined surface enlarged to have the same shape as a funnel at an end of the cylindrical portion.