MXPA97001461A - Catodi rays tube - Google Patents

Abstract

In the present invention, a cathode ray tube is provided. In the cathode ray tube, since a multiplicity of notches are formed on the inner surface of an inner shield, an electron beam that is emitted from an electronic gun and that strikes the inner surface of the shield is effectively prevented. inside, it is deposited in the fluorescent film of the panel, to thereby provide clearer screen images.

Description

CRT FIELD OF THE INVENTION The present invention relates to a cathode ray tube, and more particularly to a cathode ray tube having an improved inner shield.

BACKGROUND OF THE INVENTION As shown in Figure 1, a cathode ray tube is generally provided with a mouth 3 and a panel 2 which are sealed together. The terminal portion of the mouth 3 is provided with an electronic barrel 4 for emitting electron or electron beams, and the mouth 3 is provided with a deflection yoke about an outer circumference of a neck portion 3a for deflecting the bundles of electrons emitted from the electronic cannon 4. The inner surface of the panel 2 is coated with a fluorescent film 2a to emit light as the electron beams collide therein, thereby forming an image. Also, there is a shadow mask slightly deviated from the inner surface REF: 24170 of the panel 2 having a multiplicity of holes 6a passing through the beam. The shadow mask 6 is attached to a structure 7, and an inner shield 8 is attached to the structure 7 to prevent external magnetism such as terrestrial magnetism from influencing the electron beams emitted from the electronic gun 4. With reference to the Figure 2, an electron beam 4b deflected by the deflection yoke 5 is deflected from a desired route 4a due to an error in the magnetic force of the deflection yoke 5 and then strikes the interior surface of the interior shield 8 and is reflected. The reflected electron beam 4c passes through an unwanted hole in the shadow mask and generates color contamination.

BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a cathode ray tube having an improved inner shield in order to prevent electron beams emitted from an electronic gun, and then colliding with the interior of the inner shield, to be deposited on a fluorescent film of a panel.

To achieve the above object of the present invention, a cathode ray tube is provided, which includes a mouthpiece having an electronic barrel in a neck portion thereof, a panel sealed to the mouthpiece and having an interior surface in the mouth. which is coated with a fluorescent film, a shadow mask installed inside the panel, a structure to support the shadow mask, and an inner shield to prevent external magnetism from influencing electron beams emitted from the electron gun, where the surface The interior of the inner shield is formed with a multiplicity of notches to prevent the electron beam striking the interior surface thereof from being reflected towards the fluorescent film.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing object and advantages of the present invention will become more apparent when describing in detail a preferred embodiment thereof with reference to the accompanying drawings in which: Figure 1 is a sectional, schematic view showing a conventional cathode ray tube; Figure 2 is a sectional, schematic view showing an electron beam that is reflected from an inner shield of the cathode ray tube shown in Figure 1; Figure 3 is a sectional, schematic view showing a cathode ray tube according to the present invention;; Y Figure 4 is a sectional, schematic view showing an electron beam that is reflected from an inner shield of the cathode ray tube shown in Figure 3.

DETAILED DESCRIPTION OF THE INVENTION With reference to Figure 3, a conventional cathode ray tube according to the present invention, similar to the cathode ray tube, illustrated with reference to Figures 1 and 2, is provided with a panel 20 and a mouth 30 which is they seal with each other The inner surface of the panel 20 is coated with a fluorescent film 21. The terminal portion of the mouth 30 is provided with an electronic gun 40 for emitting electron beams, and a deflection yoke 50 around the outer circumference of a neck portion 31 for deflecting the electron beams emitted from the electron gun 40. A shadow mask 60 having a multiplicity of pass holes 61 of the beam is fixed to one side of a structure 70, which is slightly offset from the inner surface of the panel 20. Attached to the other side of the structure 70, there is an inner shield 80 to prevent external magnetism such as terrestrial magnetism from influencing the electron beam emitted from the electronic barrel 40. Meanwhile, the inner surface of the inner shield 80 is formed with a multiplicity of notches 81. Here, the notches 81 can be formed by stamping. In the above cathode ray tube, as shown in Figure 4, in the event that an electron beam 42 emitted from the electronic gun 40 deviates from a desired path 41 towards the inner surface of the inner shield 80, the beam of electrons 42 strikes the inner surface of the notch 81. In this way, the electron beam 42 striking the notch 81 is completely reflected from the interior surface of the notch 81 at the same angle as the angle indicated with respect to the interior of the notch 81. However, since the inner surface of the notch 81 has a small radius of curvature, the electron beam 42 striking the inner surface of the notch 81 is prevented from being reflected towards the coated fluorescent film 21 in panel 20. Accordingly, it is prevented that the reflected electron beam 43 is deposited on an undesired portion of the fluorescent film 21 through the passage holes of the laser beam. 60 shade, to reduce color contamination in this way. In accordance with the cathode ray tube of the present invention, since the inner surface of the inner shield 80 has a multiplicity of notches 81, the electron beam 42 striking the inner shield is prevented from becoming an undesired portion of the shield. the fluorescent film 21 and the structural strength of the inner shield 80 is improved. Also, in the cathode ray tube, due to a plurality of projections formed in. the outer surface of the inner shield 80, which corresponds to the notches 81, disperses external magnetism such as terrestrial magnetism, so that the penetration of external magnetism can be prevented effectively. As described above, in the cathode ray tube according to the present invention, since a multiplicity of notches are formed on the inner surface of the inner shield, an electron beam that is emitted from the barrel is effectively prevented. electronic and that hits the inner surface of the inner shield, is deposited in the fluorescent film of the panel, to thereby provide clearer screen images.

It is noted that in relation to this date, the best method known by the applicant to carry out the present invention, is the conventional one for the manufacture of the objects to which it refers. Having described the invention as above, the content of the following is claimed as property:

Claims (2)

1. A cathode ray tube including a mouthpiece having an electronic barrel in a neck portion thereof, a panel sealed to the mouthpiece and having an inner surface on which a fluorescent film is coated, a shadow mask installed inside of the panel, a structure to support the shadow mask, and an inner shield to prevent external magnetism from influencing the electron beams emitted from the electronic cannon, characterized in that the inner surface of the inner shield is formed with a multiplicity of notches to prevent that the electron beam striking the inner surface thereof is reflected towards the fluorescent film.

2. A cathode ray tube according to claim 1, characterized in that the outer surface of the inner shield is formed with a multiplicity of projections corresponding to the notches.