KR100213785B1 - Cathode-ray tube - Google Patents

Abstract

The present invention relates to a magnetic shield of a color cathode ray tube, and in particular, by dispersing a magnetic field concentrated at the corner of the cathode ray tube by the inflow of an external magnetic field to the center of the cathode ray tube, it is possible to significantly reduce the misresist generated at the corner of the cathode ray tube. This aims to improve the color purity.

In order to realize this, the present invention forms a corner of the corner portion where the long side and the short side of the inner shield meet each other, and attaches a magnetic material having a high permeability greater than the permeability of the inner shield on both sides of the corner.

Description

Magnetic shield of color cathode ray tube

The present invention relates to a color cathode ray tube, and more particularly to a magnetic shield for shielding an external magnetic field acting on an electron beam.

In the general color cathode ray tube, as shown in FIG. 1, a panel 1 having a fluorescent film formed on its inner surface and a funnel 2 coated with conductive graphite on its inner surface are sealed with a fusion glass in a furnace at about 450 ° C. An electron gun 3 for generating an electron beam 9 is mounted on the neck portion 7 of the funnel, and a shadow mask 4, which is a color-selective electrode, is provided inside the panel 1 by a frame 5. It is supported, and a deflection yoke 8 is mounted on the outer circumferential surface of the panel 1 to deflect the electron beam from side to side.

In the figure, reference numeral 6 denotes an inner shield.

In the color cathode ray tube configured as described above, when an image signal is input to the electron gun 3, hot electrons are emitted from the cathode of the electron gun, and the emitted electrons accelerate and focus toward the panel 1 by the voltage applied from each electrode of the electron gun. It will go through.

At this time, the electrons are adjusted by the magnetic field of the deflection yoke 8 mounted on the neck of the panel, and the adjusted electron beam is scanned by the deflection yoke 8 to the inner surface of the panel. Color selection is performed while passing through the slots of the shadow mask 4 coupled to the side frame 5, and the selected electron beams collide with respective fluorescent films on the inner surface of the panel to emit light to reproduce the image signal. The inner shield 6 serves to prevent the electron beam from being deflected due to the influence of geomagnetism when the electron beam passes through the slot of the shadow mask 4 and reaches the fluorescent film.

The electron beam 9 emerging from the electron gun 3 is deflected under the influence of the geomagnetism, which causes the phenomenon of leaving the original orbit. However, it is difficult to block the influence of the earth's magnetic field on the screen axis of the color cathode ray tube.

That is, since the electron beam passing through the mask 4 lacks the correspondence to the horizontal magnetic field of the axial component, the electron beam is out of the orbit and hits other colors, causing deterioration of the image.

In order to solve this problem, the inner shield 6 is attached. As the shield material, a thin metal plate having soft magnetic current is used, and this thin inner shield is joined by a fixing pin which is bonded to the frame 5. have. At this time, since the inner shield 6 formed at a predetermined interval to face the panel is made of a magnetic material, the external magnetic field flowing into the cathode ray tube flows through the inner shield to reduce the external magnetic field generated inside the cathode ray tube.

The corner portion of the inner shield has the highest magnetic field distribution due to the nature of the magnetic field. Since the factor that substantially affects the color purity quality of the cathode ray tube is the miss register of the largest portion of the magnetic field in the cathode ray tube, in order to reduce the high magnetic field of the inner shield corner portion, the long side portion of the inner shield ( 6a) or a hole 11 acting as a magnetoresistance was formed in the short side portion 6b. This hole 11 serves to reduce the mis-resist of the cathode ray tube corner portion causing color purity problems by dispersing the magnetic field concentrated in the corner portion of the inner shield to the center portion of the cathode ray tube.

However, even if the conventional inner shield is provided with a hole acting as a magnetoresistance in the magnetic shield to reduce the magnetic field focused on the cathode ray tube corner portion, the external magnetic field flowing into the cathode ray tube is still concentrated in the corner portion as shown in FIG. In addition, the magnetic field of the corner portion flows through the hole into the three-dimensional space to generate misresistance, thereby deteriorating cathode ray tube color purity.

In addition, since the corner angle of the inner shield is small within 100 degrees, the magnetic field focused at the corner portion easily flows into a three-dimensional space outside the corner portion, and thus, it is easy to generate a miss resist, thereby further reducing the cathode ray tube color purity.

The present invention has been invented to solve the problems of the prior art as described above, and forms a corner of the corner portion where the long side portion and the short side portion of the inner shield meets, and both sides of the corner portion of the high permeability greater than the permeability of the inner shield By attaching the magnetic material, the object is to distribute the magnetic field concentrated in the corner portion to the center of the cathode ray tube.

1 is a cross-sectional view of a typical color cathode ray tube.

Figure 2 shows a conventional inner shield, (a) is a plan view, (b) is a perspective view.

Figure 3 shows the external magnetic field flowing into the conventional cathode ray tube, (a) is the overall state diagram, (b) is a (A) enlarged view of the part.

Figure 4 shows the inner shield of the present invention, (a) is a plan view, (b) is a perspective view.

5 is another embodiment of the present invention inner shield.

Figure 6 shows an external magnetic field according to the present invention, (a) is the overall state diagram, (b) is an enlarged view of part B of (a).

7 is a magnetic field distribution diagram according to the conventional and the present invention inner shield.

8 is a state of the mis-register according to the conventional and the present invention inner shield.

Explanation of symbols on the main parts of the drawings

1 panel 2 funnel

4: shadow mask 5: frame

7: electron gun 8: deflection yoke

106: inner shield 106a: long side

106b: short side 106c: corner

106d: Magnetic material

The present invention is described in detail below with reference to FIGS. 4 to 7.

First, the structure of the present invention inner shield 106 is as follows.

As shown in FIGS. 4 and 5, a magnetic material having a magnetic permeability 1.5 times higher than the permeability of the inner shield on the side of the edge portion of the inner shield 106 where the pair of long side portions 106a and the pair of short side portions 106b contact each other. (106d) is attached, the corner corner (106c) shape of the inner shield 106 has a corner angle of 100 ~ 160 to form a polygon to form a magnetic field in the inner corner at the corner corner corner Flows well so that it is not focused on the corner.

As a method of attaching the magnetic material 106d having a magnetic permeability of 1.5 times or more than the magnetic permeability of the inner shield, the magnetic piece may be attached by using a method of attaching a magnetic piece of 1.5 times or more or applying a magnetic paint. If the permeability is less than 1.5 times, the shielding effect of the attached magnetic material is almost insignificant.

When the electron beam is emitted from the electron gun of the color cathode ray tube in this configuration, the external magnetic field flowing into the cathode ray tube does not flow into the three-dimensional space outside the corner as shown in FIG. It flows on the corner part and flows into the corner part, and is distributed to the center part of the cathode ray tube.

Therefore, the misresistance of the cathode ray tube corner, which affects the color purity of the cathode ray tube, is reduced, which is applied to the X, Y, and Z axis directions of the cathode ray tube in the same principle.

7 is a comparative view of magnetic field distribution in a cathode ray tube, in which a is an inner shield of the prior art, and b is an inner shield according to the present invention. As a result of using the inner shield 106 of the present invention from FIGS. 7 and 8, the miss resist is larger than the misresisted by the conventional inner shield 6 in the center portion of the cathode ray tube, but actually affects the color purity of the cathode ray tube. It can be seen that the amount is greatly reduced in the corner portion where the misresist is large.

As described above, the inner shield structure of the present invention disperses the magnetic field concentrated at the corner of the cathode ray tube by the inflow of an external magnetic field to the center of the cathode ray tube, thereby significantly reducing the misresist occurring at the corner of the cathode ray tube, thereby improving color purity. Has the effect of improving.

Claims (5)

A panel coated with a fluorescent surface on an inner surface, a shadow mask coupled to the inside of the panel, a frame supporting the shadow mask to maintain a predetermined distance from the panel, and coupled to a rear end of the frame to shield the geomagnetic field. An inner shield, a funnel coupled to a rear end of the panel to maintain an internal vacuum state, a reinforcement band surrounding the outer surface of the panel, and a neck portion of the funnel to emit electron beams of R, G, and B; In the color cathode ray tube composed of an electron gun, The inner shield is a magnetic shield of the color cathode ray tube, characterized in that the corner of the corner portion where the long side and the short side meet each other, the magnetic material having a high permeability greater than the permeability of the inner shield is attached to a predetermined position. The method of claim 1, Magnetic corner of the color cathode ray tube, characterized in that the corner of the corner is formed from 100 to 160. The method of claim 1, The magnetic material of the high permeability magnetic shield of the color cathode ray tube, characterized in that more than 1.5 times the permeability of the inner shield. The method of claim 1, The magnetic shield of the magnetic permeability of the high magnetic permeability of the color cathode ray tube, characterized in that attached to both sides of the corner of the polygon. The method of claim 1, The magnetic material of the high magnetic permeability is a magnetic shield of the color cathode ray tube, characterized in that provided by attaching a magnetic piece or applying a magnetic paint.

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