JPH05325815A - Internal magnetic shield for cathode-ray tube - Google Patents

Abstract

PURPOSE:To reduce man-hours at the time of welding a shield to a color selecting mechanism mask by forming a protrusive part in an outer side steel plate in an overlapped part of steel plates forming a magnetic shield, so as to increase supporting strength in the case of loading the shield. CONSTITUTION:Protrusive parts (projection) 20 formed by drawing work and right/left symmetrically provided in four locations of a B part in overlapped parts 19 between an A part 7 of steel plate having a side wall 9 in a long side and B part 8 of steel plate having a side wall 10 on a short side. Two sets of the A part 7 and B part 8 are opposed and welded in a frame shape. Accordingly, an internal magnetic shield 2 is firmly and stably supported by the protrusive part 20 and further by double steel plate thickness. Thus by supporting the shield 2 loaded in a double part position with no adhesion, a large amount can be supplied by increasing strength, and man-hours can be reduced at the time of welding the shield to a color selecting mechanism mask.

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 for a cathode ray tube and, more particularly, to an internal magnetic shield for a cathode ray tube which does not cause inconveniences such as "scratching" at the top and bottom during loading.

[0002]

2. Description of the Related Art Geomagnetism exists inside a cathode ray tube (CRT) used in a color television (TV). As a means for preventing the deviation of the electron beam affected by the geomagnetism, an internal magnetic shield (Inner Magnetic Shield:
IMS) is known. This IMS is used by being welded to the frame of the color selection mechanism mask.

FIG. 3 is a perspective view for explaining the structure of a cathode ray tube (CRT). As shown in FIG. 3, the CRT is mainly a funnel 1 shown in FIG. 3A and an internal magnetic shield (IMS: inner magnetic shield) shown in FIG. 3B.
2, the color selection mechanism mask (AG: aperture grille) 3 of FIG. 3 (c), and the panel 4 of FIG. 3 (d). The IMS 2 and the AG 3 form the funnel 1 in the order shown in FIG. It is assembled between the panels 4. Further, the IMS 2 is welded and fixed to the frame of the AG 3 at a predetermined position as described above.

In FIG. 3A, 5 is a neck tube, and an electron gun 5a is arranged in the neck tube 5 to emit an electron beam.

The IMS 2 described above may be stacked (loaded) in several stages in the course of its manufacturing process. In this case, since each IMS naturally has the same shape, it overlaps exactly with the upper and lower sides, causing so-called "spotting" and becoming difficult to separate. Therefore, a structure has been devised to prevent the "clogging" of the IMS.

FIG. 4 shows a conventional I for preventing the above-mentioned scatter.
It is a perspective view which shows MS (internal magnetic shield) structure.

The IMS 2 is composed of an A part 7 and a B part 8 as shown in FIG. 4, corresponding to the long side and the short side of the CRT panel. The A part 7 and the B part 8 are the long sides, respectively. The side wall 9 and the short side wall 10 are provided to protect the electron beam from the geomagnetism.

In the conventional IMS 2 shown in FIG. 4, a part of the side wall is folded back to the lower end of each side wall of the A part 7 and the B part 8 so that the upper and lower shielded products do not cause "spotting" with each other when they are stacked. The tongue-shaped support piece 12 formed was provided (in the figure, two pieces are provided on each side wall for a total of eight pieces). Figure 5
It is the schematic which piled up IMS2 which provided the said support piece 12, and each IMS2 is slightly floated up and down by the support piece 12, and upper and lower shield products can be easily separated.

Further, as a second method for preventing the above-mentioned scatter between the IMS 2 in the related art, as shown in FIG. 6, there are three places (two facing each other) on the plane portion continuing to each side wall of the IMS 2. 2 locations on one of the A parts,
There is known a structure in which a convex portion 13 (projection) is formed on one of the other A parts and two convex portions 13 and one convex portion forming position are alternately changed up and down.

[0010]

In the above-described first structure for preventing nicks, the holes 14 are formed in the side walls of the A component on the long side and the B component on the short side of the IMS. The geomagnetic drift characteristic was worse than in the absence, and the supporting piece 12 was weak in strength because it was the thickness of the A component 7 or B component 8, that is, only one piece, and the number of stacking steps was small, resulting in poor man-hours. ..

Further, in the structure in which the convex portion (projection) 13 is provided on the plane portion of the IMS 2, the A component 7 or the B component is used.
Since the shape of the component 8 has two types, that is, the A component 7 having two convex portions and the A component 7 having one convex portion, the cost for the mold increases, and the IMS
Assembly man-hours increased.

[0012] Therefore, an object of the present invention is to provide an internal magnetic shield for a cathode ray tube in which the number of steps is reduced by improving the geomagnetic drift characteristics and increasing the strength to enable large-volume loading. ..

[0013]

According to the present invention, there is provided an internal magnetic shield for a cathode ray tube in which at least two steel plates are partially overlapped and connected in a frame shape.
This is solved by an internal magnetic shield for a cathode ray tube, characterized in that a protrusion is provided on the outer steel plate of the overlapping portion.

Further, according to the present invention, the above-mentioned problem is that, in an internal magnetic shield for a cathode ray tube in which two sets of steel plates facing each other are partially overlapped by welding and connected in a frame shape, the outer steel plate of the overlapping portion is projected. This is solved by an internal magnetic shield for a cathode ray tube, which is characterized in that a portion is provided.

In the present invention, it is preferable that the protrusion is formed by drawing or folding.

[0016]

According to the present invention, the convex portion 20 is formed on the outer (upper) steel plate of the superposed portion 19 of the steel plate forming the magnetic shield by drawing or the like. Therefore, the steel plate is present also on the lower side (inner side) of the convex portion, and when the IMS 2 is loaded (stacked), the upper and lower I
Since the MS is supported, the supporting strength can be increased, and the upper and lower IMS can be easily separated.

[0017]

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

FIG. 1 shows an internal magnetic shield (IM) of the present invention.
It is a perspective view showing an example of (S).

In FIG. 1, the same elements as in the prior art are designated by the same reference numerals.

In the present embodiment, as shown in FIG. 1, the B part of the superposition part 19 of the A part 7 of the steel plate having the long side wall 9 and the B part 8 of the steel plate having the short side wall 10 (the outer steel plate) )
4 projections by projection processing (projection) 2
0 is provided symmetrically. Two sets of each of the A part 7 and the B part 8 face each other and are welded in a frame shape by resistance welding or the like.

FIG. 2 is a view showing a state in which the IMS 2 in which the convex portion 20 is formed on the overlapping portion 19 as shown in FIG. 1 is stacked (loaded), and each IMS 2 has the symmetrical convex portion 20 and Because of the double steel plate thickness, it is firmly and stably supported. The thickness of the IMS 2 is about 0.3 mm, and the protrusion 2
0 may be about 0.5 to 1 mm protruding.

The stacking of this IMS is shown in FIG.
Color selection mechanism mask 3 (Aperture grill: A
G), which is carried out when supplying to a welding attachment device (IMS welding machine), and the IM with the convex portion 20 of the present embodiment.
For S2, good work was done efficiently without any scumming between the IMS top and bottom.

In the above embodiment, the convex portion 20 of the overlapping portion 19 of the A component 7 and the B component 8 is formed by drawing, but a structure in which a part of the upper component of the overlapping portion is cut and folded back may be used.

[0024]

As described above, according to the present invention,
Since the stacking of the internal magnetic shield (IMS) can be supported at the position of the double part without any click (adhesion), it is possible to supply a large amount by increasing the strength. Therefore, it is possible to reduce the number of steps for welding the IMS and the color selection mechanism mask.

Further, since no hole (opening) is formed unlike the case of the conventional tongue-shaped support piece, the geomagnetic drift characteristic is also improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an internal magnetic shield (IMS) of the present invention.

2 is a P arrow view of the IMS shown in FIG. 1 and its loading schematic diagram.

FIG. 3 is a perspective view showing a configuration of a cathode ray tube.

FIG. 4 is a perspective view showing an example of a conventional IMS.

5 is a view of the IMS of FIG. 4 as seen from the direction of the arrow Q and a schematic view of its loading.

FIG. 6 is a schematic plan view showing another example of a conventional IMS.

[Explanation of symbols]

 1 Funnel 2 Internal Magnetic Shield 3 Color Selection Mechanism Mask (AG) 4 Panel 5 Neck Tube 5a Electron Gun 7 A Part 8 B Part 9 Long Side Side Wall 10 Short Side Side Side Wall 12 Tongue-shaped Support Piece 13, 20 Projection (Projection) ) 14 holes 19 overlapping part

Claims (3)

[Claims] 1. An internal magnetic shield for a cathode ray tube comprising at least two steel plates, which are partially overlapped and connected in a frame shape, wherein a projection is provided on an outer steel plate of the overlapped portion. Internal magnetic shield for pipes. 2. An internal magnetic shield for a cathode ray tube, comprising: two sets of steel plates facing each other, partially overlapped by welding and connected in a frame shape, wherein a projection is provided on an outer steel plate of the overlapping part. Internal magnetic shield for cathode ray tube. 3. The internal magnetic shield for a cathode ray tube according to claim 1, wherein the projection is formed by drawing or folding.