JP3480977B2 - Internal magnetic shield and cathode ray tube using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal magnetic shield having an improved shield effect and a cathode ray tube using the same.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional internal magnetic shield (IM
It is a schematic diagram of a configuration of a color cathode ray tube including S), and a part thereof is shown in a cross section.

As shown in FIG. 3, a color cathode ray tube (CR
T) 1 is an electron gun 4 in the outer circumference of a panel 2 and a funnel 3 made of glass, a color selection mechanism 7 having a mask 7a arranged in proximity to a fluorescent screen 6 on the back surface of the panel 2, and a pyramidal main body with an upper part cut An internal magnetic shield 8 having a portion, a beam shield 9 and the like are provided. This color cathode ray tube 1
Then, an electron beam 10 emitted from the electron gun 4 is deflected horizontally and vertically around a deflection center P by a deflection yoke (not shown) attached to the outside of the cathode ray tube to reproduce an image on the fluorescent screen 6. To do. This electron beam is adversely affected by an external magnetic field such as terrestrial magnetism and causes color shift.
An internal magnetic shield 8 is provided to shield the external magnetic field that causes this color shift.

The color selection mechanism 7 is stretched over the frame A member 5a, the frame A member 5a facing the horizontal frame, the vertical frame B member 5b holding the facing frame A member 5a facing each other at the ends thereof. It is composed of a mask (metal grid) 7a.

The inner magnetic shield 8 is arranged by welding or clipping the bottoms of two pairs of opposite sides to the respective side surfaces of the frame A member 5a and the frame B member 5b. However, the welding to the frame A member 5a is limited to the case of the large cathode ray tube. In the figure, the outermost electron beam (orbit) is indicated by the alternate long and short dash line 10. Further, reference numeral 12a denotes a bottom portion for attachment to the frame A member 5a, and 12b denotes a bottom portion for attachment to the frame B member 5b. A plurality of each mounting bottom portion is arranged at a corner portion, an intermediate portion, and the like.

[0006]

The inner magnetic shield of the color cathode ray tube is, as shown in FIG. 4 which is an enlarged view of the main part of FIG. 3, clearly shown in FIG. The distance between 10 and the inner magnetic shield 8 was as large as D1, and a sufficient shielding effect was not obtained.

In view of the above problems, it is an object of the present invention to provide an internal magnetic shield having an improved shield effect, especially at the corners of the cathode ray tube, and a cathode ray tube using the same.

[0008]

In order to solve the above-mentioned problems, an internal magnetic shield according to claim 1 of the present invention has a square pyramid whose upper part is cut in order to avoid an external magnetic field with respect to an electron beam in a cathode ray tube. In the internal magnetic shield having a main body of the shape, the mounting bottom of the main body is attached to the vertical frame of the frame for color selection mechanism of the cathode ray tube, in the corner of the cathode ray tube among the mounting bottom. The facing portion is bent to the outermost electron beam orbital side, and a magnetic shield portion for closing the facing portion to the corner portion is formed.

Further, in the internal magnetic shield according to claim 2 of the present invention, the magnetic shield part is located inside the opposed vertical frames constituting the color selection mechanism frame, and the magnetic shield part It is characterized in that the mounting bottom portion is bent so that the entirety follows the outermost electron beam trajectory. Further, the cathode ray tube using the internal magnetic shield according to claim 3 of the present invention has a quadrangular pyramid-shaped main body whose upper part is cut in order to avoid an external magnetic field with respect to the electron beam emitted from the electron gun. In the cathode ray tube using the internal magnetic shield, in which the mounting bottom of the main body is mounted on the vertical frame of the frame for color selection mechanism behind the front panel, the corner of the front panel is opposed to the corner of the front panel in the mounting bottom. The part to be bent is bent to the outermost electron beam orbital side, and a magnetic shield part for closing the part facing the corner part is formed. Further, in the cathode ray tube using the internal magnetic shield according to claim 4 of the present invention, the magnetic shield part is located inside the vertical frames facing each other constituting the frame for the color selecting mechanism, and the magnetic shield part is provided. The above steps should be taken so that the entire part follows the outermost electron beam trajectory.
It is characterized in that the attached bottom part is bent.

[0010]

According to the inner magnetic shield 18 of the present invention, the inner magnetic shield facing the corner portion of the cathode ray tube 1 is removed.
Since the attached bottom portion is bent toward the electron beam trajectory 10 side to form the shield portion 13a, a higher shield effect can be obtained at the corner portion where the external magnetic field has a large influence.

Further, in the present invention, since the corner bottom portion of the internal magnetic shield associated with the vertical frame 5b of the frame for the color selecting mechanism 7 is the shield portion 13a, the magnetic shield can be easily formed at the corner portion.

[0012]

Embodiments of the internal magnetic shield according to the present invention and a cathode ray tube using the same will be described below with reference to the drawings.

FIG. 1 is a schematic view of the structure of a color cathode ray tube provided with an embodiment of an internal magnetic shield according to the present invention, a part of which is shown in cross section. FIG. 2 is an enlarged view of a main part of FIG. In the configuration shown in FIGS. 1 and 2, the same components as those in FIGS. 3 and 4 described in the related art are denoted by the same reference numerals.

As shown in the enlarged view of FIG. 2, the internal magnetic shield 18 shown in FIG. 1 has a frame B member 5b of the conventional color selecting mechanism 7 at the corner (corner) of the CRT.
A corner shield portion 13a formed by bending the attachment bottom portion 13 used for welding or clipping to the inside as shown by the arrow, that is, the electron beam orbit 10 side (reducing the distance to D2) is provided. . The attachment bottom portion 13 to the frame B member shown in the figure is in a state of being welded to the intermediate portion where the influence of the external magnetic field is small.

As described above, although the corner shield portion 13a is shown only at the two corner portions on the left and right in FIG. 1, the connecting piece (frame B member) is formed on all four corner portions of the CRT panel as described above. It is arranged so that the bottom part (attachment to) is bent inward to approach the electron beam (the distance is reduced from D1 to D2).

As described above, the internal magnetic shield of the present embodiment is substantially the same as the conventional structure described above except that the corner portion is improved, and therefore its details are omitted.

[0017]

As described above, according to the internal magnetic shield of the present invention, the vertical frame of the frame for the color selection mechanism of the cathode ray tube has the quadrangular pyramid main body with the upper part cut.
In the case where the mounting base portion of the main body portion is attached to the arm, of which the mounting base portion, and a position facing the corner portion of the cathode ray tube is bent to the outermost electron beam trajectory side, facing the corner portion A magnetic shield part for closing the part is formed. With this configuration, it is possible to obtain a high shield effect against an external magnetic field such as the earth's magnetism as compared with the conventional internal magnetic shield in the corner portion of the cathode ray tube. Further, according to the cathode ray tube using the internal magnetic shield according to the present invention, the above internal magnetic shield is applied. Therefore, it is possible to provide an internal magnetic shield having an enhanced shield effect against an external magnetic field and a cathode ray tube using the internal magnetic shield.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a color cathode ray tube including an embodiment of an internal magnetic shield according to the present invention.

FIG. 2 is an enlarged schematic view of a main part of an internal magnetic shield according to the present invention.

FIG. 3 is a schematic configuration diagram of a color cathode ray tube including a conventional internal magnetic shield.

4 is an enlarged schematic view of a main part of the internal magnetic shield shown in FIG.

[Explanation of symbols]

1,11 color cathode ray tube 2 panels 3 funnel 4 electron gun 5a Frame A member 5b Frame B member 6 phosphor screen 7-color selection mechanism 7a mask 8,18 Internal magnetic shield 10 electron beam (orbit) 12a Bottom part attached to frame A member 12b, 13 Bottom part of attachment to frame B member 13a Corner shield part

Claims (4)

(57) [Claims] 1. A vertical pyramid frame for a color selection mechanism of a cathode ray tube, comprising a main body of a quadrangular pyramid whose upper part is cut in order to avoid an external magnetic field against an electron beam in the cathode ray tube.
In internal magnetic shield attaching base portion of the body portion is attached to the frame, of the mounting base portion, bent to the electron beam orbit side of the site outermost facing the corner portion of said cathode ray tube, the corners An internal magnetic shield, characterized in that a magnetic shield portion is formed to close a portion facing the. Wherein said magnetic shield portion is positioned inside said longitudinal frame opposed constituting the color selecting mechanism for a frame, and, along the electron beam orbit of the total outermost of the magnetic shield section The inner magnetic shield according to claim 1, wherein the mounting bottom portion is bent. 3. In order to avoid an external magnetic field to an electron beam emitted from an electron gun, a rectangular pyramid-shaped main body having an upper portion cut off is provided on a vertical frame of a color selection mechanism frame at the rear of the front panel. In a cathode ray tube using an internal magnetic shield to which the mounting bottom of the main body is mounted, in the mounting bottom, a portion facing the corner of the front panel is bent to the outermost electron beam orbit side, A cathode ray tube using an internal magnetic shield, characterized in that a magnetic shield portion for closing a portion facing the corner portion is formed. Wherein said magnetic shield portion is positioned inside said longitudinal frame opposed constituting the color selecting mechanism for a frame, and, along the electron beam orbit of the total outermost of the magnetic shield section The cathode ray tube using the internal magnetic shield according to claim 3, wherein the mounting bottom portion is bent.