JPH11329275A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the magnetic shielding characteristic from being deteriorated in an image plane corner part with respect to a magnetic field in a lateral direction of a tube face by providing a V-shaped cut part in a lateral side face to enhance shielding performance for a magnetic field in an axial direction of a tube in an internal magnetic shield. SOLUTION: In a color cathode ray tube 1, having a substantially cone-shaped cylindrical body formed with four members of upper and lower members and right and left sideface members and provided with an internal magnetic shield 8 for removing the effects of an external magnetic field related to an electron beam which is incident from an electron gun 7 into a color selection electrode 3, recessed cut parts which are formed by cutting electron gun sides of the right and left sideface members of the shield 8 into recessed shapes are provided in the left and right sideface members, and a shielding plate 16 projected with a prescribed width to a color selection electrode 3 side in the vicinity of corner parts of the cylindrical body is formed integrally with the respective sideface members.

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 and, more particularly, to an improvement of an internal magnetic shield mounted in a tube to prevent a problem such as a color shift due to a deflection of an electron beam due to an external magnetic field such as terrestrial magnetism. is there.

[0002]

2. Description of the Related Art FIG. 8 is a perspective view showing a main part of a conventional color cathode ray tube, FIG. 9 is a perspective view showing a main part of an internal magnetic shield of the conventional color cathode ray tube, and FIG. It is explanatory drawing explaining the flow of the magnetic flux of a tube surface left-right direction. In the color cathode ray tube 1 shown in FIG. 8, reference numeral 2 denotes a face plate panel portion having a fluorescent screen, 3 denotes a color selection electrode provided inside the face plate panel portion 2, and 4 denotes a frame supporting the color selection electrode 3. . This frame 4
Is composed of a pair of opposing H members 41 and a pair of V members 42 that are attached across the pair of H members 41. The color selection electrode 3 is attached across the H members, and is attached to the V members 4.
2, tension is applied. The frame 4 supporting the color selection electrodes 3 is held on the inner wall of the face plate panel 2 via a holding member (not shown).
Reference numeral 5 denotes a funnel portion that covers the entirety, 6 denotes a neck portion that covers the electron gun, 7 denotes an electron gun, and 8 denotes an internal magnetic shield installed so as to surround the electron beam emitted from the electron gun 7.

[0003] When the orbit of the electron beam fluctuates under the influence of an external magnetic field such as terrestrial magnetism, the color cathode ray tube 1
It is known that unwanted phosphors emit light, which leads to undesirable results such as color shift. In order to remove the influence of such an external magnetic field, an internal magnetic shield 8 is attached along the funnel 5 from the color selection electrode 3. As shown in FIG. 9, the internal magnetic shield 8 is formed as a substantially cone-shaped cylindrical body by four members, that is, an upper surface member 9, a lower surface member 10, a right side member 11, and a left side member 12 using a thin plate material. ing. (Hereinafter, members 9 to 12 are abbreviated as upper surface, lower surface, right side surface, and left side surface.) In order to enhance the shielding performance against a magnetic field in the axial direction of the tube, the inner magnetic shield 8 has left and right side surfaces as shown in FIG. The electron beam incident sides 11 and 12 are cut in a V-shape. In FIG. 9, reference numeral 81 denotes an edge, which is a portion provided for fixing the internal magnetic shield 8 to the V member 42.

FIG. 10 shows the flow of a magnetic field in the left-right direction of the surface of the internal magnetic shield 8 of such a conventional color cathode ray tube. As is apparent from FIG. 10, the magnetic field in the left-right direction on the tube surface flows along the left side surface 12 of the internal magnetic shield and flows to the upper and lower surfaces 9 and 10 of the internal magnetic shield.
It passes through the V-cut portion of the left side surface 12 and tends to flow toward the inner magnetic shield upper and lower surfaces 9 and 10. V above
After passing through the cut part, the inner magnetic shield upper and lower surfaces 9,1
Since the magnetic flux heading for zero crosses the electron beam, the trajectory of the electron beam is bent. For this reason, a problem of causing a color shift has occurred particularly in a screen corner portion.

[0005]

In the conventional color cathode ray tube, the internal magnetic shield is provided with a concave cut portion cut into, for example, a V-shape on the left and right side surfaces in order to enhance the shielding performance against the magnetic field in the axial direction of the tube. In addition, there is a problem that the magnetic shield characteristics at the corners of the screen are deteriorated with respect to the magnetic field in the horizontal direction on the tube surface.

On the other hand, as an internal magnetic shield of a color cathode ray tube, there is, for example, one disclosed in Japanese Patent Application Laid-Open No. 6-243794. As shown in FIG. 11, the internal magnetic shield has a portion 162 in which the left and right side shield plates 161 also extend in the vertical direction. For this reason, when a magnetic field in the horizontal direction of the tube surface, the magnetic flux guided to the left and right side shield plates 161 flows from the left and right side surfaces of the internal magnetic shield to the upper and lower surfaces, while the magnetic flux flows from the portion 162 extending to the upper and lower surfaces to the upper and lower surfaces. And adversely affects the electron beam emitted from the electron gun toward the screen corner. Therefore, this internal magnetic shield has a problem that the shield performance against the magnetic field in the horizontal direction of the screen cannot be improved. In addition, since there is a portion 162 extending in the vertical direction, it is necessary to precisely control interference with the frame and the face plate panel on the outside thereof, so that there is a problem that workability is poor.

In the internal magnetic shield disclosed in Japanese Utility Model Laid-Open No. 5-62948, a shield plate 163 is independently attached to the frame 4 as shown in FIG. In addition, the inner magnetic shield 8 body and the shield plate 163
The magnetic flux does not easily flow through the internal magnetic shield 8 but flows to the frame 4 and then to the upper and lower surfaces of the internal magnetic shield over the space. Therefore, this internal magnetic shield does not have the effect of attracting a part of the magnetic flux to the shield plate 163 and reducing the magnetic flux passing through the V cut portion and intersecting the electron beam. It cannot be improved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a shield plate projecting toward the color selection electrode with a predetermined width is provided on each of left and right side members having a cut inner magnetic shield. A color cathode ray tube with improved magnetic shielding performance against the magnetic field in the tube axis direction as compared to the conventional one, without preventing the magnetic shielding characteristics against the magnetic field in the tube axis direction by lowering the magnetic shield characteristics against the magnetic field in the horizontal direction of the tube surface by being provided integrally with the member. The purpose is to obtain.

[0009]

A color cathode ray tube according to the present invention has a substantially cone-shaped cylindrical body formed by four members of upper and lower surface members and left and right side members, and is incident on a color selection electrode from an electron gun. A color cathode ray tube provided with an internal magnetic shield for removing the effect of an external magnetic field on an electron beam to be emitted, wherein a concave cut portion is formed on the right side surface and the left side surface member of the internal magnetic shield so that the electron gun side is concavely formed. In addition, a shield plate protruding toward the color selection electrode with a predetermined width only in the left and right side directions in the vicinity of the corner of the cylindrical body is provided integrally with each side member.

The concave cut portion is cut in a V-shape. The V-shaped cut rate of the concave cut portion is 10 to 70%. The concave cut portion is cut in a trapezoidal shape. Further, the cut rate of the trapezoidal shape of the concave cut portion is 10 to 70%. Furthermore, the width of the shield plate is 40% or less of the length of the bottom sides of the right and left side members.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a perspective view showing a main part of a 21-inch color cathode ray tube according to Embodiment 1 of the present invention. FIG. 2 is an explanatory diagram for explaining the flow of magnetic flux in the horizontal direction of the tube surface of the internal magnetic shield according to Embodiment 1. FIG. 3 is an explanatory diagram illustrating the flow of magnetic flux in the tube axis direction of the internal magnetic shield according to the first embodiment. 1 to 3, the same parts as those in FIGS. 8 to 10 are denoted by the same reference numerals, and description thereof will be omitted. Reference numeral 16 denotes a shield plate provided integrally with the left and right side surfaces 11 and 12 of the internal magnetic shield 8.
The shield plate 16 is provided so as to protrude toward the color selection electrode 3 with a predetermined width only in the left and right side surfaces 11 and 12 at the corners of the cylindrical body that is the main body of the internal magnetic shield 8. In other words, the shield plate 16 is provided so as to cover the V member 42 of the frame 4.

Next, the structure of the internal magnetic shield 8 will be described with reference to FIG. The width w of the shield plate 16 is 50 mm and the height h is 45 mm. Also, the left and right side surfaces 11, 12
Is 300 mm, the upper side B is 166 mm, the height C along the inclined surface is 120 mm, the lower side D of the upper and lower surfaces 9 and 10 is 330 mm, and the upper side E is 190 mm. In addition, the upper sides of the upper and lower surfaces 9 and 10 are provided with folds 17 for maintaining strength, and the width H is 8 mm. The V-shaped cut rate is 20%. When F is the depth of the V-shaped cut along the inclined surface and C is the height along the inclined surface, the cut rate is (F / C) × 100 (%).

Next, the operation of the shield plate 16 will be described.
FIG. 2 shows the flow of magnetic flux in the horizontal direction on the tube surface of the internal magnetic shield according to the first embodiment. In FIG. 2, since the left and right side surfaces 11 and 12 have V-shaped cuts, the magnetic flux ma that has passed through the cut portions is applied to the inner magnetic shield 8.
To the upper and lower surfaces 9, 10. Then, this magnetic flux intersects with the electron beam emitted from the electron gun toward the corner of the screen, causing a color shift. But,
Since the shield plates 16 are provided on the left and right side surfaces 11 and 12, a part of the magnetic flux is attracted to the shield plates 16 like mb. Therefore, the magnetic flux passing through the cut portion and intersecting the electron beam is reduced. As described above, the amount of color misregistration at the screen corner can be reduced.

The flow of magnetic flux in the tube axis direction is as follows.
As shown in FIG. That is, the magnetic flux H is guided to the upper and lower surfaces 9 and 10 of the internal magnetic shield 8 and is attracted to the color selection electrode 3. At this time, a vertical component (y-axis component) of the magnetic flux is generated, and this component causes a color shift orthogonal to the tube axis component of the electron beam I. However, due to the presence of the shield plate 16, a part of the magnetic flux H
6 and flows to the frame 4 close to the shield plate. Due to this phenomenon, a part of the magnetic field is a component in the horizontal direction of the tube surface (x
(Axial component). Thereby, the magnetic shield performance is improved. Note that FIG. 3B is a diagram described in a different method from FIG.

According to the first embodiment of the present invention, as described above, by controlling the flow of the magnetic flux, the magnetic flux intersecting the electron beam of the color cathode ray tube 1 can be reduced, and the color shift of the screen can be prevented. .

FIG. 4 shows the left and right side surfaces 11, 11 of the internal magnetic shield 8 in the 21-inch color cathode ray tube shown in FIG.
The width w of the 12 shield plates 16 is 50 mm, and the height h is 45.
mm, cut width BH = 1 on the upper side of left and right side surfaces 11 and 12
FIG. 6 is a diagram illustrating a relationship between a V-shaped cut rate with respect to a left-right magnetic field in a tube surface and a beam movement amount that causes a color shift, fixed at 50 mm. In FIG. 4, reference numeral 4a denotes a beam movement amount of the conventional color cathode ray tube, and 4b denotes the first embodiment.
Represents the amount of beam movement of the color cathode ray tube by the following equation. As can be seen from this figure, when the V-shaped cut rate is 50% or less, the inclination of the beam movement amount is gentler than in the conventional color cathode ray tube. According to the first embodiment, it can be seen that the increase in the beam movement amount in the left-right magnetic field on the tube surface due to the V-shaped cut is suppressed.

However, if it exceeds 50%, the amount of beam movement sharply increases, and if it exceeds 70%, the shielding performance is conversely lower than that of the conventional color cathode ray tube. This is because the magnetic flux flowing from the left and right directions is attracted to the cut portion and flows to the upper and lower surfaces 9 and 10. However, since the cut is too deep, the magnetic flux on the left and right side surfaces does not affect the beam trajectory. This is because the magnetic flux flows into the shield plate 16 and the magnetic flux concentrates around the corner. In addition, the cut rate is 1 from FIG.
In the case of less than 0%, it can be seen that there is almost no difference between the color cathode ray tube of the first embodiment and the conventional one.

As described above, in the color cathode ray tube of the first embodiment, the left and right side surfaces 11, 12 of the internal magnetic shield 8 are provided.
By combining the V-shaped cut with a cut rate of 10% to 70% with the shield plates 16 provided on the left and right side surfaces, it is possible to reduce an increase in beam movement due to the magnetic field in the left and right direction of the tube surface due to the cut. . FIG. 4 shows an example in which the upper cut width BH is 150 mm.
Even if the upper cut width BH is large or small, the relationship between 4a and 4b is almost the same, although the absolute value of the beam movement amount is large or small.

Embodiment 2 FIG. 5 is a perspective view showing a main part of the internal magnetic shield according to the second embodiment. In FIG. 5, portions denoted by the same reference numerals as those in FIGS. 1 to 3 indicate the same portions, and different points from Embodiment 1 are left and right side surfaces 11 and 1.
This is the point that the cut of No. 2 was changed to a trapezoidal cut. In the color cathode ray tube according to the second embodiment, since the internal magnetic shield 8 has a trapezoidal cut, the magnetic flux in the horizontal direction of the tube surface passing through the cut portion is attracted to the upper and lower surfaces 9 and 10 of the internal magnetic shield 8. . Then, this magnetic flux intersects with the electron beam emitted from the electron gun toward the corner of the screen, causing a color shift. However, since the shield plates 16 are provided on the left and right side surfaces 11 and 12, a part of the magnetic flux is attracted to the shield plates 16. Therefore, the magnetic flux passing through the cut portion and intersecting the electron beam is reduced.
As described above, the amount of color misregistration at the screen corner can be reduced. This is the same as in the first embodiment.

The magnetic flux in the tube axis direction is guided to the upper and lower surfaces 9 and 10 of the internal magnetic shield 8 and is attracted to the color selection electrode 3. However, the presence of the shield plates 16 on the left and right side surfaces 11 and 12 Part of the magnetic flux is shield plate 1
6 flows to the frame 4 close to the shield plate 16. This is also the same as in the first embodiment. As described above, the second embodiment is similar to the first embodiment,
By controlling the flow of magnetic flux, the color cathode ray tube 1
And the magnetic flux intersecting with the electron beam can be reduced, and the color shift of the screen can be prevented.

FIG. 6 shows the left and right side surfaces 11, 11 of the internal magnetic shield 8 in the 21-inch color cathode ray tube shown in FIG.
The width w of the 12 shield plates 16 is 50 mm, and the height h is 45.
FIG. 6 is a diagram illustrating a relationship between a trapezoidal cut rate with respect to a magnetic field in the left-right direction of the tube surface and a beam movement amount that causes color shift, with the angle θ in FIG. When G is the depth of the trapezoidal cut along the inclined surface and C is the height along the inclined surface, the trapping cut rate is (G / C) × 1.
00 (%).

In FIG. 6, reference numeral 6a denotes a beam movement amount of the conventional color cathode ray tube, and 6b denotes a beam movement amount of the color cathode ray tube according to the second embodiment. As can be seen from this figure, when the trapezoidal cut rate is 50% or less,
Compared with the conventional color cathode ray tube, the inclination of the beam movement amount is gentler. According to the second embodiment, it can be seen that an increase in the beam moving amount in the left-right magnetic field in the tube surface due to the trapezoidal cut is suppressed.

However, if it exceeds 50%, the amount of beam movement sharply increases, and if it exceeds 70%, the shielding performance deteriorates in contrast to the conventional color cathode ray tube. The reason is the same as in the first embodiment. In addition, the cut rate is 10 from FIG.
%, It can be seen that there is almost no difference between the color cathode ray tube of the second embodiment and the conventional one.

As described above, in the color cathode ray tube according to the second embodiment, the left and right side surfaces 11, 12 of the internal magnetic shield 8 are provided.
By combining the trapezoidal cut with a cut ratio of 10% to 70% with the shield plates 16 provided on the left and right side surfaces, it is possible to reduce an increase in the beam movement amount due to the magnetic field in the left and right direction of the tube surface due to the cut. Although FIG. 6 shows an example in which θ is 60 degrees, the relationship between 6a and 6b is almost the same even though the value of θ is changed, although the absolute value of the beam movement amount changes.

Embodiment 3 FIG. 7 is a diagram showing, as an example, a relationship between the width of the shield plate 16 provided on the left and right side frames of the internal magnetic shield and the beam movement amount with the V-shaped or trapezoidal cut rate fixed at 20%. It is. The width of the shield plate 16 is set to the left and right side surfaces 11 and 12 of the internal magnetic shield.
Is shown as a percentage of the length of the base. In FIG. 7, 7b shows the relationship between the width of the shield plate 16 and the beam movement amount in the tube surface left-right direction magnetic field, and 7a shows the relationship between the width of the shield plate 16 and the beam movement amount in the tube axial direction magnetic field. . As can be seen from 7b in FIG. 7, the beam movement amount in the left-right magnetic field on the tube surface is 0 when the width of the shield plate 16 is zero.
From 25% to about 25%, but it starts increasing when it exceeds about 25%, and 0% when it exceeds 40%, that is, the beam movement amount becomes larger than when the shield plate 16 is not provided. This is because the magnetic flux near the frame corner which affects the beam trajectory flows through the shield plate 16 and decreases, but when the shield plate width becomes large, the shield plate 16 is moved to the magnetic flux at the intermediate portion which does not originally affect the beam trajectory. This is because the magnetic flux that has flowed and leaked from the shield plate 16 affects the beam trajectory.

On the other hand, the amount of movement of the beam with respect to the magnetic field in the tube axis direction decreases as the width of the shield plate increases, as shown at 7c. From the above points, the inner magnetic shield left and right side 1
When the width of the shield plate 16 provided in the first and the second 12 is 40% or less,
It is preferable to apply the present invention to the color cathode ray tube according to the first or second embodiment.

In the above embodiment, the case of the internal magnetic shield of the 21-inch color cathode ray tube has been described.
Regardless of the inch size, it goes without saying that the same effect can be obtained by implementing the present invention.

[0028]

As described above, the present invention has a substantially cone-shaped cylindrical body formed of four members, the upper and lower members and the left and right members, and is provided for protecting an electron beam incident on a color selection electrode from an electron gun. A color cathode ray tube having an internal magnetic shield for removing the influence of a magnetic field, wherein a right and left side members of the internal magnetic shield are provided with concave cut portions in which the electron gun side is cut in a concave shape, and a cylindrical body is provided. A shield plate protruding toward the color selection electrode with a predetermined width only in the left and right side direction in the vicinity of the corner is provided integrally with each side member. Since the magnetic flux intersecting with the electron beam is reduced, the shielding performance is not reduced, and the magnetic flux flowing through the upper and lower surfaces of the internal magnetic shield is transmitted through the shield plate for the magnetic field in the axial direction of the tube. By flowing to the frame Ri,
The shielding performance is improved, and color shift on the screen can be prevented.

The V-shaped or trapezoidal cut rate is set to 10
Since it is set to 70%, the shielding performance is improved, and the effect of preventing color shift on the screen can be obtained in an optimal state.

Further, since the width of the shield plate is set to 40% or less of the length of the bottom side of the right and left side members,
The shield performance is improved, and the effect of preventing color shift on the screen can be obtained in a more optimal state.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a color cathode ray tube according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a flow of a magnetic flux in a left-right direction of a tube surface of an internal magnetic shield according to the first embodiment.

FIG. 3 is an explanatory diagram illustrating the flow of magnetic flux in the tube axis direction of the internal magnetic shield according to the first embodiment.

FIG. 4 is a diagram showing a relationship between a V-shaped cut rate and a beam movement amount with respect to a left-right magnetic field on a tube surface in the first embodiment.

FIG. 5 is a perspective view showing a main part of an internal magnetic shield according to a second embodiment.

FIG. 6 is a diagram showing a relationship between a trapezoidal cut rate and a beam movement amount with respect to a left-right magnetic field on a tube surface in the second embodiment.

FIG. 7 is a diagram showing a relationship between a width of a shield plate and a beam movement amount in the third embodiment.

FIG. 8 is a perspective view showing a main part of a conventional color cathode ray tube.

FIG. 9 is a perspective view showing a main part of an internal magnetic shield of a conventional color cathode ray tube.

FIG. 10 is an explanatory diagram illustrating the flow of magnetic flux in the left-right direction of the tube surface of the conventional internal magnetic shield.

FIG. 11 is a perspective view showing another example of a conventional internal magnetic shield.

FIG. 12 is a schematic sectional view showing still another example of the conventional internal magnetic shield.

[Explanation of symbols]

1 color cathode ray tube, 2 panel section, 3 color selection electrode, 4
Frame, 5 funnel, 6 neck, 7 electron gun, 8 internal magnetic shield, 9, 10 upper and lower surfaces of internal magnetic shield, 11, 12 left and right sides of internal magnetic shield, 16 shield plate.

Claims (6)

[Claims] An internal magnet having a substantially cone-shaped cylindrical body formed of four members, an upper and lower surface member and left and right side members, for removing the influence of an external magnetic field on an electron beam incident on a color selection electrode from an electron gun. A color cathode ray tube having a shield, wherein a right and left side member of the internal magnetic shield is provided with a concave cut portion in which the electron gun side is cut into a concave shape, and the left and right portions are provided near corner portions of the cylindrical body. A color cathode ray tube, wherein a shield plate protruding toward the color selection electrode with a predetermined width only in a side surface direction is provided integrally with each side member. 2. The color cathode ray tube according to claim 1, wherein the concave cut portion is cut in a V-shape. 3. The V-shaped cut rate of the concave cut portion is 1
3. The color cathode ray tube according to claim 2, wherein the content is 0 to 70%. 4. The color cathode ray tube according to claim 1, wherein the concave cut portion is cut in a trapezoidal shape. 5. A trapezoidal cut rate of the concave cut portion is 1
5. A color cathode ray tube according to claim 4, wherein said color cathode ray tube is 0 to 70%. 6. The color cathode ray tube according to claim 2, wherein the width of the shield plate is 40% or less of the length of the bottom sides of the right and left side members.