JPS5923346Y2 - color picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color picture tube equipped with an inner shield and an electron shield.

In general, when a color picture tube is in operation, the electron beam emitted from the electron gun must strike extremely precisely into a phosphor layer that emits red, green, and blue light, which is regularly deposited on the inner surface of the panel. However, after the electron beam is emitted from the electron gun, it is affected by stray magnetic fields generated for various reasons in the so-called electron beam path where it impinges on the phosphor layer.
As a result, only images with many color shifts can be reproduced on the panel.

For example, this is the case when a shadow mask type color picture tube is operated in the presence of another magnetic field such as the earth's magnetic field.

For this reason, such color picture tubes, particularly wide-angle deflection tubes, are sometimes provided with an internal magnetic shield inside the funnel of the envelope.

Furthermore, in a shadow mask type color picture tube, an overscanned electron beam passes through the gap between the shadow mask and the inside of the panel side wall while being reflected, and this passing electron beam can cause undesired phosphor layers to be irradiated. To cause sudden light emission, a so-called electron shield is usually provided between the inside of the panel side wall and the shadow mask to block this overscanned electron beam.

Next, FIG. 1 shows an example of a color picture tube equipped with an internal magnetic shield and an electron shield.

That is, a phosphor surface 11 has a phosphor layer regularly deposited on the inner surface of the phosphor layer, which emits light in three colors of red, green, and blue upon impingement of an electron beam.
a panel 12 with a funnel 1 on this panel 12;
3, a neck 15 in which an electron gun 14 that emits an electron beam is mounted, a shadow mask 16 facing the panel 12 at a predetermined distance, and a mask frame 17 that supports this shadow mask 16. An internal magnetic shield 18 and an electron shield 19 are fixed to the funnel 13 and extend along the funnel 13.
can be shielded, but the opening end surface 17 of the mask frame 17
Electron beam 20 colliding with a Reflected electron beam 2 of b
0b' cannot be shielded, and since the internal magnetic shield 18 is standing, the electron beam 20C that hits the inside of the internal magnetic shield 18 becomes a reflected electron beam 200' and is an unwanted phosphor. Shoot through the layers.

In order to prevent this reflected electron beam 20C', a flange 18□ as shown by the broken line can be attached to the electron gun side end of the internal magnetic shield, but this flange 18□ is effective electron beam 20C'.
Since it is not effective unless it is provided close to d, considerable precision is required in the parts and assembly.

Another example of a color picture tube provided with an internal magnetic shield is shown in FIG.

That is, a panel 22 has a phosphor surface 21 on the inner surface of which is regularly deposited a phosphor layer that emits light in three colors of red, green, and blue upon impact of an electron beam, and a funnel 23 is attached to this panel 22.
A neck 25 is connected to the neck 25 through which an electron gun 24 for emitting an electron beam is mounted, a shadow mask 26 is disposed opposite to the panel 22 at a predetermined distance, and a mask frame 27 supports the shadow mask 26. It has a substantially L-shaped internal magnetic shield 28 that is fixed to the funnel 23 and extends along the funnel 23. However, unlike the above-mentioned example, such an internal magnetic shield 28 has an overscan electron beam. 30a is required, such as an electron shield.

Recently, power-saving designs have made considerable progress, and for this reason, the shape of the funnel 23 is made as close to the effective electron beam 30b as possible to reduce the deflection power, thereby shielding the overscanned electron beam. In order to do this, the internal magnetic shield 28 must be placed fairly close to the funnel inner wall, which also requires high precision.

The dimensions of the inner magnetic shield 28 are, for example, the first side 28 fixed to the mask frame 27 is 15 mm;
A second side 28□ with a vertical dimension of 44 mm is provided along the funnel at an inclination angle of about 60° from the end of the side 28□ on the funnel side, and from the end of the second side 282 on the electron gun side, A collar of approximately 15 mm was provided parallel to the first side 28 of the flap.

The present invention has been devised in view of the problems of the prior art described above, and an object of the present invention is to provide a color picture tube equipped with an internal magnetic shield that is simple in structure and inexpensive to mold.

Next, an embodiment of the color picture tube of the present invention will be explained with reference to FIG.

That is, the color picture tube of this embodiment has a panel 32 having a phosphor surface 31 on the inner surface of which a phosphor layer that emits light in three colors of red, green, and blue is regularly deposited upon the impingement of an electron beam. , a neck 3 connected to this panel 32 via a funnel 33 and equipped with an electron gun 34 that emits an electron beam inside.
5, a neck 35 connected to this panel 32 via a funnel 33 and equipped with an electron gun 34 for emitting an electron beam therein, a shadow mask 36 disposed opposite to this panel 32 at a predetermined interval; shadow mask 3
A first side 381 is fixed to the mask frame 37 that supports the mask frame 37, and the end edge of the first side on the side of the funnel 33 has a desired height bent at a substantially right angle in the direction opposite to the panel 32. The second side 38□ and the first side at the edge of this second side.
The magnetic body 38 has a substantially U-shaped cross section and has a third side 383 that is substantially parallel to the side of the magnetic body 38 .
a is prevented by the third side 383, and the third side 383,
The unnecessary electron beam 40C adjacent to the effective electron beam 40b is shielded by one of the open end edges of the first side 38□, and the height of the second side 382 of the magnetic material 38 is set to the color picture tube. By setting a value suitable for , reflection of the electron beam inside the magnetic body 38 can be completely prevented.

Of course, in this case, depending on the shape of the funnel 33, the second side 38
The height of □ is limited, and there are doubts about the shielding effect of the earth's magnetic field, but since the area of the third side 383 can be made sufficiently large, the shielding effect is sufficient, and is particularly good for wide-angle deflection tubes. be.

Furthermore, since the magnetic body 38 has a simple U-shaped cross section, it is easy and inexpensive to manufacture, and it is also lightweight as an internal magnetic shield, making it resistant to vibrations of the color picture tube. However, very good effects were obtained.

The length of the first side of the magnetic body 38 used in this example is 15
mm, the height of the second side is 8 mm, and the length of the third side is 20 mm.
mm, the shielding effect of the electron beam by the earth's magnetism is almost the same as that of the second conventional example, and the mold cost of this example was 500,000 yen, and the conventional mold cost 1,500,000 yen.

As mentioned above, the color picture tube of the present invention has a great effect because it can be used as an inner shield and an internal magnetic shield by using a magnetic material of a simple shape.

[Brief explanation of the drawing]

1 and 2 are explanatory sectional views showing different examples of conventional color picture tubes, and FIG. 3 is an explanatory sectional view showing one embodiment of the color picture tube of the present invention. 11.21.31... Fluorescent surface, 12,22.3
2...Panel, 16°26.36...
Shadow mask, 17, 27. 37...Mask frame, 18, 28... Inner ring magnetic shielding plate, 3
8...Magnetic material.

Claims (1)

[Scope of utility model registration request] A panel that has a phosphor layer regularly deposited on its inner surface that emits light in three colors of red, green, and blue when an electron beam hits it, and is connected to the panel via a funnel and emits an electron beam inside. a neck on which an electron gun is attached; a shadow mask that is opposed to the panel at a predetermined distance; a first side is fixed to a mask frame that supports the shadow mask; a second side bent at an edge at a substantially right angle in a direction opposite to the panel; and a third side substantially parallel to the first side at an edge of the second side.
1. A color picture tube comprising a substantially U-shaped cross section consisting of sides, and a magnetic material, the magnetic material serving as both an electron shield and an inner shield.