JP3525636B2 - Color cathode ray tube - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube used for displays such as color televisions and computer monitors.

[0002]

2. Description of the Related Art A conventional color cathode ray tube has a glass bulb in which a front panel portion having a fluorescent surface on the inner surface, a funnel portion and a neck portion are sequentially formed, and a color selection electrode having a large number of transmission holes at one end side. A frame for supporting each of the cylindrical magnetic shield plates on the end side, and a frame for facing the color selection electrode to the phosphor screen, and arranged in the neck portion, an electron beam is emitted to the phosphor screen through the transmission hole of the color selection electrode. An electron gun for irradiation is provided, and an external magnetic field such as geomagnetism between the color selection electrode and the electron gun is shielded by a magnetic shield plate to deflect and scan the electron beam shielded by the external magnetic field. .

[0003]

However, in such a conventional color cathode ray tube, since the radius of curvature of the peripheral portion of the color selection electrode is made small as a measure against the doming of the color selection electrode, the fluorescence of the front panel portion is reduced. The distance between the surface and the color selection electrode is larger in the front panel area than in the center of the front panel area. Especially, the electron beam irradiated to the fluorescent surface around the front panel area is affected by the external magnetic field such as the earth's magnetism. However, there is a problem in that it is not possible to accurately perform the deflection scanning on the predetermined fluorescent screen and the color shift occurs.

The present invention reduces the influence of an external magnetic field such as terrestrial magnetism and accurately deflects and scans an electron beam after passing through a transmission hole of a color selection electrode onto a predetermined fluorescent screen, thereby producing a color cathode ray tube with high color purity. Is provided.

[0005]

A color cathode ray tube according to the present invention is a color bulb having a glass bulb in which a front panel portion having a fluorescent surface on the inner surface, a funnel portion and a neck portion are sequentially formed, and a large number of transmission holes on one end side. A frame for supporting the selection electrodes, respectively, a cylindrical magnetic shield body on the other end side, and facing the color selection electrode to the phosphor screen, and a transmission hole of the color selection electrode arranged in the neck portion. An electron gun assembly for irradiating the phosphor screen with an electron beam via
Surrounding the corners of the frame and
And a frame made of a magnetic material protruding toward the phosphor side
Is equipped with a separate shield plate, and the long side direction of the frame
And the lengths in the short side direction are W1 and W2, respectively.
Length of the shield plate in the long side direction and the short side direction of the frame
Are L1 and L2 respectively, 0 <L1 ≦ W1 × 1
It is characterized in that 0% and 0 <L2 ≦ W2 × 10% .

With this configuration, the shield means shields an external magnetic field such as geomagnetism between the color selection electrode and the phosphor screen.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a color cathode ray tube according to an embodiment of the present invention has a glass bulb 5 formed by sequentially forming a front panel portion 2 having a fluorescent screen 1 on an inner surface thereof, a funnel portion 3 and a neck portion 4. And a color selection electrode 8 made of low carbon Al killed steel (hereinafter referred to as a mild steel plate) having a large number of through holes 7 on one end side 6, and a magnetic shield body 10 made of a trapezoidal cylindrical mild steel plate on the other end side 9. And supports the phosphor screen 1
And a frame 11 made of a mild steel plate having a rectangular cross section for facing the color selection electrode 8 to each other, and arranged in the neck portion 4 and passing through the transmission hole 7 of the color selection electrode 8 to the phosphor screen 1 with an electron beam. The electron gun structure 13 for irradiating the laser beam 12, the shield means 15 provided in the corner portion 14 of the frame 11 for shielding the external magnetic field between the color selection electrode 8 and the phosphor screen 1, and the frame 11 made of glass. And a supporting means 16 for supporting the valve 5.

Further, as shown in FIG. 2, the shield means 15 includes the corner portions 14a, 14b, 14 of the frame 11.
c, 14d, and shield plates 15a, 15b, 15c, 15d, which are made of mild steel plates and project from the frame 11 to the vicinity of the phosphor screen 1, respectively.
It is fixed to 14b, 14c, 14d by welding. Then, the respective shield plates 15a, 15b, 15c,
15d is formed in an L-shape and has a long side 11 of the frame 11.
The length L1 in the direction along a is defined as the long side 11a of the frame 11.
And the length L2 in the direction along the short side 11b of the frame 11 is 10% to 50% of the length W2 of the short side 11b of the frame 11.

In the above embodiment of the present invention, the shield means 15 includes the shield plates 15a, 15b, 15c, 1
Although there are four parts of 5d, one shield means 15 may be formed on a cylindrical shield plate, and the outer peripheral surface of the frame 11 may be surrounded by this shield plate.

Next, the operation and effect of the color cathode ray tube will be described. In the color cathode ray tube according to the embodiment of the present invention, the magnetic shield 10 is provided between the color selection electrode 8 and the electron gun assembly 13, so that the geomagnetism or the like between the color selection electrode 8 and the electron gun assembly 13 is generated. The external magnetic field of the frame 11 is blocked, and the corners 14a, 14b, 14c, 14 of the frame 11 are blocked.
Since the shield plates 15a, 15b, 15c, and 15d are provided on d, an external magnetic field such as geomagnetism between the color selection electrode 8 and the fluorescent screen 1 around the front panel portion 2 is shielded. As a result, the electron beam 12 after passing through the transmission hole 7 of the color selection electrode 8 can be accurately deflected and scanned onto a predetermined fluorescent screen 1 over the entire fluorescent screen 1 of the front panel portion 2, thereby improving color purity. You can

[0012]

EXAMPLES Next, examples for confirming the effects of the present invention will be described.

The color cathode ray tube of the embodiment of the present invention shown in FIG. 1 (hereinafter referred to as the product of the present invention) is a 68 cm-110 ° TV.
A tube was used. Then, the shield means 15 and the frame 11
The dimensional relationship between the front panel 2 and the front panel 2 is shown in FIG. 2, and L1 of the shield plates 15a, 15b, 15c and 15d is used.
Is about 137 mm, L2 is about 104 mm, H is about 63 m
m and t are about 0.3 mm, W1 of the frame 11 is about 54
6 mm, W2 is about 415 mm, and each shield plate 15a, 15b, 15 facing the inner surface of the front panel 2
The end surfaces of c and 15d are 2 with respect to the inner surface of the front panel section 2.
A gap of mm is provided along the curve of the inner surface of the front panel portion 2. Further, the gap between the phosphor screen 1 of the front panel portion 2 and the color selection electrode 8 is about 16 m at the peripheral central portion Z1 (the Y dimension is 20 mm) on the upper and lower surfaces of the front panel portion 2 shown in FIG.
m, the peripheral corners Z2 (X
And the Y dimension is 20 mm each) is about 30 m
m.

For comparison with this, a conventional color cathode ray tube (hereinafter referred to as a conventional product) without the shield plates 15a, 15b, 15c and 15d shown in FIG. 2 was also manufactured.

The peripheral central portion Z1 of the front panel portion 2
In the peripheral corner portion Z2 of the front panel portion 2 and the beam movement amount a shown in FIG. 3 due to the influence of external magnetism such as the earth's magnetism, the following results were obtained. 4 and 5 show the results of the product of the present invention and the conventional product.

The product of the present invention is a central portion Z around the front panel 2.
The beam movement amount a of 1 is 8 μm in the arrow direction, and the beam movement amount a of the peripheral corner portion Z2 of the front panel section 2 is 1 in the arrow direction.
In contrast with the conventional product, the beam movement amount a of the peripheral central portion Z1 of the front panel portion 2 is 10 μm in the arrow direction in the conventional product.
m, the beam movement amount a of the peripheral corner portion Z2 of the front panel portion 2 was 25 μm in the arrow direction. Therefore, in the product of the present invention, the beam movement amount a of the peripheral central portion Z1 of the front panel portion 2 was reduced by 2 μm and the beam movement amount a of the peripheral corner portion Z2 of the front panel portion 2 was reduced by 10 μm in comparison with the conventional product. The reason for this is that the electron beam 12 is affected by an external magnetic field such as the earth's magnetism, especially around the corner Z2 of the front panel, and the influence of the electron beam 12 on the shield plates 15a, 15b, 15
It is considered that the reduction was achieved at c and 15d.

Next, the shield plates 15a, 15 of the present invention product
W1 is 2 when the dimensions of L1 and L2 of b, 15c and 15d are
7mm (5% of W1), W2 21mm (5% of W2)
And W1 is 55 mm (10% of W1), W2 is 42 mm
(10% of W2) and W1 are 137 mm (25 of W1
%), W2 is 104 mm (25% of W2) and W1 is 27
3 mm (50% of W1), W2 is 207 mm (5 of W2
0%), and the peripheral corner Z2 of the front panel 2
When the beam movement amounts a due to the influence of external magnetism such as the earth magnetism were examined, the results shown in FIG. 6 were obtained.

The beam movement amount a is determined by the shield plates 15a, 1
It can be seen that the size of L1 of 5b, 15c, and 15d is 10% or more of W1 and the size of L2 is stable from 10% or more of W2. Therefore, the shield plates 15a, 15
The dimensions of b, 15c and 15d are 0 <L1 ≦ W1 × 10%
And 0 <L2 ≦ W2 × 10% is preferable.

[0019]

As described above, the present invention has the shield means for shielding the external magnetic field between the color selection electrode and the fluorescent screen, which is provided at the corner portion of the frame, so that the earth magnetism or the like can be obtained. It is possible to obtain a color cathode ray tube with good color purity that can reduce the influence of the external magnetic field and accurately deflect and scan the electron beam after passing through the transmission hole of the color selection electrode onto a predetermined fluorescent screen.

[Brief description of drawings]

FIG. 1 is a sectional view showing a color cathode ray tube according to an embodiment of the present invention.

FIG. 2 is a perspective view of an essential part showing a shield means of the color cathode ray tube.

FIG. 3 is a diagram showing the amount of beam movement of the present invention seen from the side due to the influence of an external magnetic field.

FIG. 4 is a diagram showing a beam movement amount when viewed from the front of the product of the present invention due to the influence of an external magnetic field.

FIG. 5 is a diagram showing a beam movement amount when viewed from the front due to the influence of an external magnetic field of a conventional product.

FIG. 6 is a diagram showing the beam movement amount with respect to the length of the shield plate of the present invention.

[Explanation of symbols]

2 Front panel 3 funnel part 4 neck 5 glass bulbs 8-color selection electrode 10 Magnetic shield 11 frames 12 electron beam 13 Electron gun structure 15 Shielding means

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-54816 (JP, A) JP-A-3-159031 (JP, A) Actually opened 61-166460 (JP, U) Actually opened 57- 119448 (JP, U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01J 29/02 H01J 29/07

Claims (2)

(57) [Claims] 1. A glass bulb in which a front panel portion having a phosphor screen on the inner surface, a funnel portion and a neck portion are sequentially formed, a color selection electrode having a large number of transmission holes on one end side, and a cylindrical magnetic element on the other end side. A frame for supporting each of the shields, and a frame for facing the color selection electrode to the phosphor screen, and arranged in the neck portion, and irradiating the phosphor screen with an electron beam through a transmission hole of the color selection electrode. For enclosing the electron gun structure and the corner of the frame , and
It consists of a magnetic material protruding from the frame to the phosphor side.
A shield plate separate from the frame is provided, and the lengths of the frame in the long side direction and the short side direction are respectively set.
W1 and W2, the long side of the frame of the shield plate
Direction and the length in the short side direction are L1 and L2, respectively.
0 <L1 ≦ W1 × 10% and 0 <L2 ≦ W2 × 1
A color cathode ray tube characterized by being 0% . 2. A portion of the shield plate on the side of the front panel portion.
The shape of the end surface is a shape that follows the curve of the inner surface of the full-scale panel section.
The color cathode ray tube according to claim 1, wherein the color cathode ray tube has a shape of a circle.