JPS6367306B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color picture tube, and more particularly to an internal magnetic shield mounted within the color picture tube.

Color picture tubes, especially 3-electron beam type color picture tubes equipped with a shadow mask, are susceptible to mislanding of the electron beam due to the influence of the earth's magnetism, so an internal magnetic shield is installed along the inner wall of the funnel from the shadow mask. has been done.

Next, an example of such a color picture tube will be explained with reference to FIGS. 1 and 2.

That is, a color picture tube is a rectangular picture tube on which a phosphor surface 1 is formed, in which phosphor layers emitting light in red, green, and blue colors are regularly arranged, for example, in a band shape, by the impingement of an electron beam. a shaped panel 2, a net 5 connected to the side wall 3 of this rectangular panel 2 via a funnel 4, an electron gun 6 mounted in this neck 5, and three electron beams from this electron gun 6. A shadow mask 7 is selected and made to strike each phosphor layer forming the phosphor surface 1, and this shadow mask 7 is held and supported by a panel pin implanted in the inner wall of the side wall portion 3 via a support body. mask frame 8,
A fixed side ₉₁ is fixed to this mask frame 8,
At the end edge of the fixed side ₉₁ on the funnel 4 side, there is a side ₉₂ extending toward the electron gun side, which is bent at an almost right angle in the direction opposite to the panel 2, and at the end edge of this second side ₉₂ , there is a fixed side. It is formed of an internal magnetic shield 9 having a substantially U-shaped cross section, and a side 9 ₃ that is substantially parallel to the fluorescent surface and bent to be substantially parallel to the funnel 4 and away from the funnel ₄ .

The above-mentioned internal magnetic shield 9 prevents the overscanning electron beam from the electron gun 6 at the side 9 _{3 that is substantially parallel to the fluorescent surface, and this side 9 3 and} the fixed side 9
This shielding is achieved by shielding unnecessary electron beams adjacent to the effective electron beam at one of the edges of ₁ and by setting the height of the side ₉₂ extending toward the electron gun to a value suitable for a color picture tube. Reflection of the electron beam inside the body 9 can be completely prevented. Of course, in this case, the height of the second side ₉₂ is restricted by the shape of the funnel 4, but since the area, or width, of the side ₉₃ that is approximately parallel to the fluorescent surface can be made sufficiently large, the shielding effect can be reduced. This is sufficient, and the effect is particularly good in wide-angle deflection tubes. Furthermore, the magnetic shield 9
Since it has a simple U-shaped cross section, it is easy to manufacture and inexpensive, and it also has the effect of being lightweight as an internal magnetic shield. However, when the internal magnetic shield 9 having such a structure is provided to completely surround the electron beam passage area as shown in FIG. body pieces 9a, 9b,
9c and 9b are overlapped with each other at their ends. Each of the internal magnetic shield pieces 9a, 9b, 9 is caused by resonance caused by the magnetic sound of the demagnetizing coil for demagnetization of a television receiver equipped with a color picture tube equipped with such an internal magnetic shield 9, the sound of the speaker, etc.
c and 9d will collide and generate noise. In order to prevent this phenomenon, a structure in which the internal magnetic shield pieces 9a, 9b, 9c, and 9d are mechanically connected by welding or the like may be considered, but this would significantly impair workability.

Furthermore, as another structure, as shown in FIG. 3, internal magnetic shield pieces 9a, 9 are provided only on the long side of the rectangular panel.
A structure using only c is also conceivable. However, a color picture tube provided with such internal magnetic shielding pieces 9a and 9c provides a good shielding effect when the panel is oriented south or north, but when the panel is oriented east, the fourth As shown in the figure, the horizontal magnetic field becomes like a curve 10 and the electron beam moves in the direction of the arrow 11. When facing west, the horizontal magnetic field becomes like a curve 12 as shown in Fig. 5, and the electron beam moves in the direction of the arrow 11. When the electron beam moves in the direction of arrow 13 and is further applied with a perpendicular magnetic field 14 as shown in FIG. 6, the electron beam moves in the direction of arrow 15, both of which result in mislanding of the electron beam.

The present invention has been made in view of the problems of the color picture tube described above, and an object of the present invention is to provide a color picture tube equipped with an internal magnetic shield having an extremely excellent magnetic shielding effect.

The structure of a color picture tube is almost the same as that in Figure 1, so it will be explained without using the reference numerals.The inner surface of the color picture tube is made up of phosphors that emit red, green, and blue colors when an electron beam strikes them. A rectangular panel on which regularly arranged fluorescent surfaces are adhered, a net connected to the side wall of the rectangular panel via a funnel, and an electron gun mounted in the net. Then, a color selection electrode such as a shadow mask that selects this electron beam and makes it strike each phosphor layer forming a fluorescent surface, and a panel pin that holds this color selection electrode and is embedded in the inner wall of the side wall. It is made up of a mask frame supported via a support, and an internal magnetic shield fixed to the mask frame.

Next, the main parts will be explained with reference to FIG.
That is, a shadow mask 7 in which a large number of rectangular electron beam holes 7 ₁ are bored in the longitudinal direction of a band-shaped phosphor layer, and a mask frame 8 that supports this shadow mask 7 are provided with fixed sides 19a ₁ and 19b _{1 ,} respectively. ,1
9c ₁ , 19d ₁ are fixed, and this fixed side 19a ₁ , 1
9b ₁ , 19c ₁ , 19d ₁ have first gaps 20 ₁ bent at almost right angles in the direction opposite to the panel on the funnel side edges, and corresponding to the diagonal of the panel.
20 ₂ , 20 ₃ , 20 ₄ are provided, and on both long sides of the panel, there are sides 19a 2 and 19c 2 that are wider toward the electron gun and extend toward the electron gun side, and on both short sides of the panel, sides 19a ₂ and 19c ₂ that extend toward the electron gun side are provided. Sides 19b ₂ and 19d ₂ extending toward the electron gun are provided with a narrow width 21 on the electron gun side, and edges of these sides 19a ₂ , 19b ₂ , 19c ₂ , and 19d ₂ are provided with lines substantially parallel to the fluorescent surface. Sides 19a ₃ , 19b ₃ , 19
c ₃ , 19d ₃ are provided, and these sides 19a ₃ , 19
A second gap 23 ₁ , ₂₃ 2 , 2 is provided between b ₃ , 19c ₃ , 19d ₃ to prevent the electron beam from the electron gun from leaking.
Four internal magnetic shield pieces 19a, 19b, 19 having a spatial overlapping portion that can be formed by 3 ₃ , 23 ₄
An internal magnetic shield 19 consisting of c and 19d is provided.

Next, the effects of the internal magnetic shield 19 described above will be explained with reference to FIG.

In other words, Figure 8 shows the horizontal magnetic field of the earth's magnetism (perpendicular to the page) on the internal magnetic shield 19 when the panel is oriented north.
Since M _Y is concentrated on the sides 19a ₃ and 19c ₃ of the internal magnetic shield pieces 19a and 19c provided on both long sides of the panel, a local magnetic field m _Z is generated, and this local magnetic field m _Z
The direction in which the electron beam moves is the original horizontal magnetic field.
This is completely opposite to that of M _Y , and the amount of movement of the electron beam decreases. This also applies when the panel is facing south. In this case, the sides 19 of the internal magnetic shield pieces 19b and 19d provided on both short sides of the panel
Since b ₃ and 19d ₃ are located closer to the fluorescent surface than the sides 19a ₃ and 19c ₃ of the internal magnetic shield pieces 19a and 19c provided on both long sides, it is difficult to place the panel facing north or south. Sometimes the shorter sides 19a ₃ , 19c ₃
Since the horizontal magnetic field is hardly concentrated on the long sides 19b ₃ and 19d ₃ and a sufficient local magnetic field can be generated to offset the movement of the electron beam due to the earth's magnetism, the shielding effect is better exhibited.
In this case, if a conventional internal magnetic shield having the structure shown in Fig. 2 is provided, when the panel is oriented north or south, the horizontal magnetic field will also be applied to the internal magnetic shield pieces 9b and 9d provided on the short sides. Since the electron beams are concentrated, the amount of movement of the electron beam due to the earth's magnetism is increased compared to this embodiment.

That is, by adopting the structure of this embodiment, each of the internal magnetic shields 19a and 1 of the internal magnetic shields provided on both long sides and both short sides of the panel, respectively.
There is no need to mechanically connect 9b, 19c, and 19d, and there is no noise caused by the magnetic sound of the demagnetizing coil for demagnetization or the sound of the speaker due to contact between the pieces, and the shielding effect against earth's magnetism is good. The amount of movement of the electron beam due to the earth's magnetism can be extremely reduced over the entire panel.

Next, another embodiment of the present invention will be described with reference to FIG. In the figures, the same parts as in the previous embodiment are designated by the same reference numerals and will not be particularly described.

That is, the internal magnetic shield pieces 19 on both short sides of the panel
Sides 19b ₂ and 19d ₂ extending toward the electron gun side of b and 19d
extends toward the electron gun from the sides 19b ₃ and 19d ₃ that are substantially parallel to the fluorescent surfaces of the internal magnetic shield pieces 19a and 19c on both long sides, and the side 19 extending toward the electron gun side.
The sides 19b ₃ and 19d ³ are provided from the desired positions of b ₂ and 19d ₂ in the same way as in the previous embodiment, and with this structure, when the color picture tube is oriented eastward or westward, the 2 gaps 23 ₁ , 23 ₂ , 23 ₃ ,
Since _23.4 , it has been designed to prevent the earth's magnetic field from penetrating and moving the electron beam.

Next, still another embodiment of the present invention will be described with reference to FIG. In the figures, the same parts as in the previous embodiment are designated by the same reference numerals and will not be particularly described.

That is, the internal magnetic shield pieces 19 on both long sides of the panel
a, 19c and internal magnetic shield pieces 19 on both short sides
b, 19d are integrally formed except for the sides 19a ₃ , 19c ₃ and 19b ₃ 19d ₃ which are substantially parallel to the fluorescent surface at the diagonal part of the panel, and there is no first gap and extends toward the electron gun side. Sides 19a ₂ , 19c ₂ and 19b ₂ , 1
9d ₂ forms an inclined surface. The effect is almost the same as the previous embodiment, but it is mechanically strong and the dimensions of each part can be accurately determined.

As described above, in the color picture tube of the present invention, the sides 19a ₃ and 19c ₃ that are substantially parallel to the fluorescent surface of the internal magnetic shield pieces 19a and 19c on both long sides are connected to the internal magnetic shield pieces 19b on both short sides. , 19d, side 19 parallel to the fluorescent surface
b ₃ , 19d ₃ By installing the electron gun closer to the electron gun, the influence of the earth's magnetism on the electron beam can be minimized, so the color picture tube is particularly good, with an internal electron gun arranged in a row. It is possible to obtain

[Brief explanation of drawings]

Figure 1 is a sectional view showing an example of a color picture tube equipped with an internal magnetic shield, Figure 2 is a perspective view of the internal magnetic shield, and Figure 3 is an example in which the internal magnetic shield is provided only on the long side. The perspective views shown in Figures 4 to 6 are
This is a diagram showing the movement of the earth's magnetism and electron beam when the internal magnetic shield shown in the figure is provided. Figure 4 is an explanatory diagram when the panel is facing east, and Figure 5 is an illustration when the panel is facing west. 6 is an explanatory diagram when perpendicular magnetism is applied to the panel, FIG. 7 is a perspective view showing an internal magnetic shield adapted to an embodiment of the color picture tube of the present invention, and FIG. 8 is a panel FIG. 9 is a perspective view showing an internal magnetic shield adapted to another embodiment of the color picture tube of the present invention, and FIG. FIG. 6 is a perspective view showing an internal magnetic shield adapted to still another embodiment of the color picture tube of FIG. 7... Shadow mask, 8... Mask frame, 9, 19... Internal magnetic shield, 9 ₁ , 19a ₁ ,
19b ₁ , 19c ₁ , 19d ₁ ...Fixed side, 9 ₂ , 19
a ₂ , 19b ₂ , 19c ₂ , 19d ₂ ... side extending toward the electron side, 9 ₃ , 19a ₃ , 19b 3 , 19c ₃ , 19d _{3 ...}
The side that is almost parallel to the fluorescent surface.

Claims (1)

[Scope of Claims] 1. A rectangular panel having a fluorescent surface adhered to its inner surface, a net connected to the panel via a funnel, and an electron beam from an electron gun installed in the net. In a color picture tube, the color picture tube is equipped with a shadow mask that selects and causes the electron gun to strike the fluorescent surface, and an internal magnetic shield that is fixed to a mask frame that supports the shadow mask. A side extending substantially parallel to the fluorescent surface at an end edge of the rectangular panel is located closer to the electron gun than both short sides of the rectangular panel. A color picture tube featuring 2 Selecting a rectangular panel having a fluorescent surface adhered to its inner surface, a neck connected to the panel via a funnel, and an electron beam from an electron gun installed in the neck, to illuminate the fluorescent surface. In a color picture tube comprising a shadow mask that is projected onto an optical surface and an internal magnetic shield fixed to a mask frame that supports the shadow mask, an end of a side of the internal magnetic shield that extends toward the electron gun side. Both short sides of the panel having rectangular edges are closer to the electron gun than both long sides, and the fluorescent surface is attached to the end edge of the side extending toward the electron gun on both long sides. A color picture tube characterized in that sides provided substantially parallel to the fluorescent surface on both short sides of the substantially parallel sides are provided on the fluorescent surface side.