KR100343556B1 - Inner shield structure for color Braun tube - Google Patents

Abstract

The present invention relates to an inner shield structure for a color CRT tube, wherein the same side wall portion as the long side wall is formed on the long side wall of the inner shield so that the amount of electron beam movement and the change of the vertical magnetic field of the earth's magnetic field are changed. Increasing the inner shield material characteristics, i.e. increasing the permeability or reducing the coercive force, increases the shielding of the external geomagnetic field and reduces the amount of electron beam shifting in the east-west, south-north direction. In addition, the material cost of not developing the material properties has the same effect as the conventional one.

Description

Inner shield structure for color Braun tube

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color CRT, and more particularly, to an inner shield structure for color CRT for improving the purity characteristics by reducing the amount of electron beam movement.

1 is a cross-sectional configuration of a typical cathode ray tube, a panel portion (1) which is a front glass, a funnel portion (2) combined with the front glass, a fluorescent surface portion (4) that plays a predetermined light emitting role inside the funnel, The electron gun, which is the source of the electron beam 6 for emitting phosphors, a tension mask unit 3 for selecting a color to emit a predetermined phosphor, a frame unit 7 for supporting the tension mask, and an assembly of the frame to the panel. The spring portion 8 to be coupled, the inner cathode portion 9 is sealed by a high vacuum body fixed to the frame so that the cathode ray tube is less affected by the external geomagnetism during operation.

Referring to the operation principle of the CRT according to the above configuration, the electron beam 6 is formed on the inner surface of the funnel portion 1 by the anode voltage applied to the cathode ray tube in the electron gun embedded in the neck of the funnel portion 2. When hitting the fluorescent surface portion 4, the electron beam is deflected up and down, left and right by the deflection yoke portion 5 before reaching the fluorescent surface portion to form a screen, the electric electron beam 6 is exactly a predetermined phosphor There is a magnet part 10 of the 2, 4, 6 poles to correct the trajectory to strike the to prevent color purity defects.

However, since the CRT is made of high vacuum, firecrackers can be easily caused by external impact, so that the panel part 1 is designed to have a structural strength that can withstand atmospheric pressure, and also the panel part 1 By attaching the reinforcing band 11 to the skirt of the Skirt, the stress applied to the CRT in a high vacuum state is dispersed and the impact resistance is secured.

2a and 2b is a conventional inner shield operation principle structure diagram, the magnetized inner shield is a magnetic force is generated by the micro-magnet structure, the magnetic force is to cancel the external magnetic field, constructive interference, the external magnetic field is the inner inner The path of the magnetic field is changed by the shield, and the earth's magnetic field refers to the magnetic force generated from the earth's south pole and the north pole, and can be expressed as the sum of the horizontal and vertical magnetic fields at all positions of the earth, corresponding to the Lorentz equation of Equation 1 below. The electrons are directed to the electrons, and the electrons radiated from the electron gun change the electron beam path of the geomagnetic field, thereby causing an adverse effect on the purity.

<Equation 1>

F = Q ^* [E + v × B]

At this time, if the inner shield is placed in the magnetic field region in which the external magnetic field B exists, a spin moment is formed therein, and a magnetic dipole is formed in a predetermined direction, and the inner shield is magnetized to change into a magnetic material.

On the other hand, the smaller the external magnetic field in the cathode ray tube, the better the geomagnetic shielding characteristics. Therefore, the principle of shielding the earth's magnetic field by the inner shield is theoretically considered. Under the same force as Equation 2 below.

<Equation 2>

F = Q ^* [E + v × B _DY ÷ B _CRT ]

here,

F: the force exerted by the electrons inside the cathode,

Q is the charge of electrons,

E is the strength of the electric field,

V: the speed of electrons,

B _DY : magnetic flux density by deflection yoke

B _CRT : Magnetic flux density inside cathode ray tube for external magnetic field (H)

Therefore, the magnetic flux density existing inside the cathode ray tube should be minimized, and the magnetic shield should be shielded using an inner shield. In this case, the magnetic flux density is proportional to the intensity of the magnetic field as shown in Equation 3 below. .

<Equation 3>

B = μ o * H

Also, the inner shield magnetic flux density (B _{inner shield} ) in the magnetic field where magnetization occurs is shown in Equation 4.

<Equation 4>

B inner shield = μ o * (H + M)

here,

M: magnetization of linear isotropic material M = χ _m * H,

μ: permeability,

H: external magnetic field

In addition, the magnetic flux density inside the inner shield in consideration of the magnetization of the inner shield is expressed by Equation 5 below.

<Equation 5>

B _{inner shield} = μo ^* H ^* (1 + χ _m ) = μo ^* μs ^* H

here,

B inner shield: susceptibility,

μo: Permeability in free space: 4π × 10-7 [H / m],

μs: specific permeability (constant). General magnetic material ≒ ferromagnetic μs> 1,

Diamagnetic material μs <1

At this time, the magnetic permeability increases as the magnetic permeability increases and the magnetic flux density increases as the magnetization increases, and when the magnetic flux density increases, the magnetic field is shielded by using the inner shield by changing the direction of the magnetic field toward the inner shield where magnetization occurs.

In addition, the inner shield is shielded through FIG. 3, which is an inner shield shape. V-Notch 21 reduces the north-south travel amount, which refers to the amount of electron beam movement, when the cathode ray tube is rotated 180 ° from north to south when switching from north to south. Let's do it.

4A and 4B are structural diagrams of a beam moving state due to the northern hemisphere horizontal magnetic field when there is no conventional inner shield. FIG. 4A and FIG. 4B show a method of reducing the amount of South-North movement due to the inner shield shape design. In the north direction, the amount of rotation beam movement in the counterclockwise direction is generated under the influence of the magnetic field in the tube axis direction of the cathode ray tube.

FIG. 5 is a vertical magnetic field (By) induction structure diagram of an axial magnetic field by a conventional inner shield short side V-Notch, and converts an axial magnetic field Bz into a horizontal (Bx) and vertical (By) magnetic field by the inner shield. By doing so, the amount of movement of the electron beam in the counterclockwise direction by the axial horizontal magnetic field and the amount of movement of the electron beam in the clockwise direction as it is converted into the horizontal and vertical magnetic fields are canceled, so that the amount of movement of the entire electron beam beam is reduced.

Table 1 relates to the amount of electron beam movement by the inner shield short side V-Notch.

TABLE 1

The amount of electron beam movement by inner shield short side V-Notch

Short side V-Notch depth 0 30 90 mm South-North Movement Amount (㎛) 105 83 58

The larger the inner shield short side V-Notch, the smaller the North-North electron beam movement amount. The northern hemisphere cathode cathode tube is affected by the transverse geomagnetic field in the horizontal direction. As it decreases, it increases the longitudinally changed magnetic field inside the cathode ray tube.

In addition, Table 2 shows the electron beam movement amount by the long side hole (2 times) enlargement.

TABLE 2

Long side hole number One 2 East-West Movement Amount (㎛) 73 68

Therefore, short-side V-Notch decreases the north-south electron beam movement, while increases the east-west electron beam movement, and also increases the hole area on the long side to reduce the east-west electron beam movement. There is an effect of reducing the amount of electron beam movement when changing the direction.

In order to minimize the geomagnetic shielding characteristics and the amount of electron beam movement before and after the element in the prior art as described above, when the external magnetic field is removed, a material having a small amount of residual magnetic field, that is, an inner shield material having a small coercivity or using magnetic flux inside the cathode ray tube In order to use a high permeability material that increases the density and moves the magnetic field strongly toward the inner shield, the material cost is high.

In addition, when the short side Notch depth is deepened to reduce the amount of North-South electron beam movement, there is a disadvantage in that the amount of electron beam movement increases when the east-west direction is changed. Therefore, in order to make the east-west electron beam small, the long side hole size and area are enlarged. There is a disadvantage that the effect is not great.

In order to solve the above disadvantages, the present invention provides the magnetic shielding characteristic of the CRT, that is, when the cathode ray tube is rotated in the direction, the sidewall portion of the inner side of the long side of the inner shield is reduced in order to reduce the amount of electron beam shift and the amount of electron beam shift to the vertical magnetic field change of the earth magnetic field. An object of the present invention is to provide a color Brown tube geomagnetic shielding enhancement inner shield structure for improving geomagnetic shielding properties by attaching a shielding agent having the same shape as the long side wall at regular intervals to form a long side wall layer.

In order to achieve the above object, the present invention, by forming the same side wall portion as the long side wall on the long side wall of the inner shield in a double layer to reduce the amount of electron beam movement and the amount of electron beam movement in the vertical magnetic field change of the earth's magnetic field during the rotation of the cathode ray tube It is characterized by improving the geomagnetic shielding characteristics.

1 is a cross-sectional configuration of a typical cathode ray tube,

2a and 2b is a conventional inner shield operation principle structure diagram,

3 is a conventional inner shield shape assembly structure,

4a and 4b is a structure of the beam (Beam) moving state by the northern hemisphere horizontal magnetic field when there is no conventional inner shield,

5 is a vertical magnetic field (By) induction structure diagram of an axial magnetic field by a conventional inner shield short-side V-Notch,

6A and 6B are barrel structural difference structure diagrams of a horizontal magnetic field to which the present invention is applied;

7 is an inner shield assembly structure according to the present invention.

* Explanation of symbols for main parts of the drawings

110: long side wall double layer 120: inner shield structure

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

6A and 6B are structural diagrams of a barrel shape difference of a horizontal magnetic field to which the present invention is applied. The magnetization does not easily occur due to a large half magnetic field coefficient, and parallel to the external magnetic direction, that is, the long side of the inner shield is spin by an external magnetic field. An inner shield is formed in a constant direction by forming a moment and a magnetic dipole, and an inner shield short side portion perpendicular to the direction of an external magnetic field which is changed into a magnetic material while being magnetized, and a barrel-shaped magnetic field by the inner shield. It is formed as a horizontal magnetic field in the east-west direction to increase the amount of electron beam movement.

The barrel shape difference structure of the horizontal magnetic field can reduce the electron beam shift amount by making the barrel shape of the horizontal magnetic field smoother than the sharp one.

FIG. 7 is an inner shield assembly structure diagram according to the present invention, in which the same side wall portion as the long side wall is formed as a double layer 110 on the long side of the inner shield to increase the surface area of the inner shield structure 120 and a barrel of horizontal magnetic field. By smoothing the shape, there is an advantage of reducing the east-west direction electron beam shift amount without deteriorating the north-west direction electron beam shift amount.

The gap between the double ply is at least the thickness of the inner shield, and the shape of the double ply and the area of the hole should be the same as the shape of the inner side of the long side wall.

Table 3 relates to inner shield characteristic values according to the present invention.

TABLE 3

Inner Shield Characteristic

Long side hole Double layer formation South-North Beam Movement 57 56 East-West Beam Movement 70 58

As described above, the present invention improves the characteristics by increasing the short-side V-Notch to reduce the amount of electron beam movement in the south-north direction in order to reduce the amount of electron beam movement in the east-west and south-north direction, and improves the east-west switching electron beam. In order to reduce the amount of movement, long sidewalls are formed in layers to reduce the amount of East-West electron beam movement, thereby increasing the inner shielding properties by developing the inner shield shape without increasing the inner shield raw material properties, that is, the permeability or the coercivity. Therefore, the amount of electron beam shifted in the east-west, south-north direction can be reduced to ultimately improve the purity characteristics, and the material cost of not developing the material characteristics also has the same effect as the conventional one.

Claims (6)

In the color cathode ray tube inner shield structure, By forming a double layer of the same side wall portion as the long side wall on the long side wall of the inner shield by reducing the amount of electron beam movement and the amount of electron beam movement to the vertical magnetic field change of the geomagnetic field in the direction of the cathode ray tube to improve the geomagnetic shielding characteristics Inner shield structure for color CRT. The method of claim 1, wherein the inner shield A short side portion perpendicular to the direction of the external magnetic field in which the anti-magnetic field coefficient is large so that magnetization does not easily occur; A long side part of which a spin moment by the external magnetic field is formed in a constant direction of a magnetic dipole and becomes a magnetic material while being magnetized; And An inner shield structure for a color CRT tube, which is formed of a barrel-shaped magnetic field and is made of a horizontal magnetic field in the east-west direction to increase the amount of electron beam movement. The magnetic field of claim 2, wherein the barrel-shaped magnetic field is The inner shield structure for a color CRT tube, characterized by reducing the amount of electron beam movement by gently forming the shape of the magnetic field. The method of claim 1, wherein the double ply An inner shield structure for a color CRT tube, wherein the gap between the double layers is assembled at an inner shield thickness or more. The method of claim 1, Inner shield structure for a color CRT tube, characterized in that the configuration of the double layer is configured in the same manner as the inner side of the shield side wall. The method of claim 1, wherein the area of the hole (Hole) formed in the double ply Inner shield An inner shield structure for a color brown tube, configured to be the same as that formed on the long side wall.