JP2000030630A - Convergence adjusting means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compensate misconvergence caused by the Lorentz's force produced by electron beams on both outsides among three electron beams generated in an electron gun of an inline color cathode ray tube and earth magnetism of the electron gun in its axis direction. SOLUTION: A pair of magnetic bodies are placed on the inner surface of a holder 15 to hold a ring-shaped magnet 14 so as to sandwich three electron beams from the horizontal direction of a screen and to make a part of them face each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to convergence adjusting means mounted on a neck tube of a color cathode ray tube having an in-line type electron gun.

[0002]

2. Description of the Related Art Conventionally, in a color cathode ray tube using an in-line type electron gun, a technique of bending an electron beam in an electron gun has been known in Japanese Patent Publication No. 1-229299 to obtain convergence. The principle of the convergence will be described with reference to FIG. The electron gun includes a cathode that emits electrons and a plurality of electrodes, and controls the flow rate, focusing, and the like of the electrons emitted from the cathode by applying different potentials to the plurality of electrodes. In FIG. 3, electron beams 2a, 2b, and 2c emitted from cathodes 1a, 1b, and 1c respectively correspond to G1 to G4.
After passing through the electrode 3 constituted by the above, and passing through the through hole 5 formed in the shadow mask 4 having a color selecting function, the light reaches the screen surface 6 on the inner surface of the glass panel 7 to emit the phosphor. At this time, in order to concentrate the trajectories of the electron beams 2a, 2b, and 2c on the phosphor screen surface 6 at one point, G1 to G through which the outer electron beams 2a and 2c pass.
The locus of the electron beams 2a and 2c is decentered with respect to the electron beam 2b by the inclination of the electric field formed by the potential difference between the hole 4 and each electrode.

[0003]

The principle of the occurrence of misconvergence of electron beams on both sides in an in-line type electron gun due to geomagnetism in the axial direction of the electron gun will be described with reference to FIG. FIG. 4 is a perspective view showing the trajectories of the decentered outer and outer electron beams and the center electron beam in the electron gun, and the same parts as those in FIG. 3 are denoted by the same reference numerals.

In FIG. 4, an electron beam 1a is represented by a component 1a when expressed in a rectangular coordinate system in which the axial direction of the electron gun is the Z axis.
x, 1az. Similarly, electron beam 1
c is also decomposed into components 1cx and 1cz, respectively.

Usually, when operating a color cathode ray tube,
The electron beam is affected by geomagnetism. In particular, when terrestrial magnetism is applied in the axial direction of the electron gun, the components 1ax and 1cx of the electron beams 1a and 1c are orthogonal to the terrestrial magnetism, so that a Lorentz force is generated. For example, axial direction (direction 8 in the figure)
, The electron beams 1a and 1c are decentered in the directions of 1ay and 1cy, respectively, due to Lorentz force. As a result, misconvergence occurs, and the screen quality of a display using a color cathode ray tube is significantly impaired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a convergence adjusting means capable of effectively correcting misconvergence of electron beams on both outer sides generated in the in-line type electron gun due to the operation principle. Things.

[0007]

In order to solve the above problems, a convergence adjusting means of the present invention is mounted on a neck tube of a color cathode ray tube having an in-line type electron gun for generating three electron beams, and is provided at a center of a screen. A plurality of sets of ring-shaped magnets for concentrating the three electron beams and performing color purity correction in a unit, a holder for holding the ring-shaped magnet, and the three electrons on an inner surface of the holder. And a pair of magnetic bodies disposed in the axial direction of the in-line electron gun so as to sandwich the beam and at least partially oppose each other.

In this way, the terrestrial magnetism in the axial direction of the electron gun is attenuated, and the magnetic field that cancels out the Lorentz force generated by the terrestrial magnetism in the axial direction of the electron gun and the components of the electron beams on both outer sides perpendicular to this. Is generated, and misconvergence of the electron beams on both outer sides can be corrected.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view of a color cathode ray tube to which the convergence adjusting means according to the present embodiment is mounted.
3 and 4 are denoted by the same reference numerals.

In FIG. 2, a funnel glass 9 in a wax shape is fused to a panel glass 7 of a bulb 19. A deflection yoke 10 for deflecting the electron beam up, down, left and right is mounted in the opening of the funnel glass 9. Further, inside the elongated neck tube 11 of the funnel glass 9 which is elongated, an in-line type electron gun 1 is provided.
The plane containing the trajectories of three electron beams is the bulb 19.
Is enclosed so as to include the horizontal direction of the screen surface 6 formed on the inner surface of the front surface of the screen. The electron beams 2a, 2b, and 2c generated by the electron gun 12 reach the screen surface 6 on the inner surface of the glass panel 7, and cause the phosphor to emit light. The pair of magnetic bodies 13 are arranged to face each other along the axial direction of the electron gun 12 in the horizontal direction of the screen so as to sandwich the electron beams 2a, 2b, 2c generated in the in-line type electron gun. The pair of magnetic bodies 13 are actually disposed on the inner surface of the holder of the convergence adjusting means. However, in order to clarify the positional relationship with the electron beam generated by the electron gun, FIG. This is also shown in FIG.

FIG. 1 shows convergence adjusting means according to an embodiment of the present invention.

The convergence adjusting means of the present embodiment comprises:
Plural sets of ring-shaped magnets 14 for concentrating three electron beams and correcting color purity at the center of the screen
A holder 15 for holding the ring-shaped magnet 14, and a pair of magnetic bodies 13 provided on the inner surface of the holder 15 for correcting misconvergence of both outer electron beams. When the convergence adjusting means is mounted on the outer periphery of the neck tube at the rear part of the deflection yoke, the magnetic body 16 is arranged in the horizontal direction of the screen surface so that the position as shown in FIG. In this relationship, three electron beams and a pair of magnetic materials can be placed.

The material of the magnetic body 13 is, for example, JIS
Iron-nickel magnetic alloys listed in C 2531 can be used.

According to the above configuration, a pair of magnetic materials provided so as to sandwich the three electron beams from the horizontal direction,
The terrestrial magnetism in the axial direction of the electron gun concentrates at one end of the magnetic body 13 and diverges from the other end in order to pass through the inside of the magnetic body having higher magnetic permeability. At this time, since the magnetic body 13 generates a magnetic field in the direction opposite to the terrestrial magnetism, the magnetic body 13 attenuates the axial terrestrial magnetism that passes through the color cathode ray tube,
By generating a magnetic field that cancels out the Lorentz force generated by the axial terrestrial magnetism and the components of the electron beams on both outer sides perpendicular to the axial direction, misconvergence of the electron beams on both outer sides can be corrected.

In this embodiment, the case where the magnetic body 13 has the same length as the axial length of the electron gun of the holder 15 has been described. However, the magnetic body 13 is not necessarily the same as the axial length of the holder 15. Alternatively, the axial length may be longer than the length of the holder so as to protrude from the holder so that the correction effect by the magnetic material is sufficiently obtained.

In the above embodiment, the magnetic body is rectangular, but it is needless to say that the present invention is not limited to this. Further, in the above embodiment, the case where the magnetic material is completely opposed in the horizontal direction of the screen surface has been described,
It is sufficient that at least a part of the magnetic members face each other, and the same correction effect can be obtained even if the mounting angle of the opposed magnetic members is slightly rotated with respect to the horizontal direction of the screen surface.

[0018]

As described above, the convergence adjusting device of the present invention is arranged so that the three electron beams of the color cathode ray tube are sandwiched on the inner surface of the holder and at least a part thereof faces each other. By providing a pair of magnetic bodies disposed in the axial direction of the in-line electron gun,
Misconvergence of electron beams on both outer sides can be corrected. In addition, since the pair of magnetic bodies are provided on the inner surface of the holder of the convergence adjusting device, the magnetic bodies can be easily mounted on the color cathode ray tube and the position can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a perspective view of a convergence adjusting device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a color cathode ray tube to which the convergence adjusting device according to the embodiment of the present invention is attached.

FIG. 3 is a schematic diagram for explaining a convergence state of the in-line type electron gun.

FIG. 4 is a schematic diagram for explaining misconvergence generated by a magnetic field in the axial direction of the electron gun in the inline type electron gun.

[Explanation of symbols]

 2a, 2b, 2c Electron beam 11 Neck tube 12 Electron gun 13 Magnetic body 14 Ring magnet 15 Holder

Claims (3)

[Claims] 1. A color cathode ray tube having an in-line type electron gun for generating three electron beams, mounted on a neck tube of a color cathode ray tube, for concentrating the three electron beams and correcting color purity at a central portion of a screen. A plurality of sets of ring-shaped magnets, a holder for holding the ring-shaped magnets, and the in-line so that the three electron beams are sandwiched on an inner surface of the holder and at least a part thereof is opposed to each other. A convergence adjusting means, comprising: a pair of magnetic bodies disposed in the axial direction of the electron gun. 2. The convergence adjusting means according to claim 1, wherein said pair of magnetic bodies have a length equal to an axial length of said in-line type electron gun of said holder. 3. The pair of magnetic bodies is longer than the axial length of the holder of the in-line type electron gun.
Convergence adjustment means as described.