JPH10208654A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the color slippage at the center in the up and down direction of a screen by an external magnetic flux in the tube axial direction which flows into the sidewalls on the longer side of the inner magnetic shield of a color cathode-ray tube. SOLUTION: A window 16 is provided to sidewalls 9 and 10 at the longer side of an inner magnetic shield 8, and this window 16 consists of a horizontal side 19 parallel to the end side 17 on the electron gun side of the sidewalls 9 and 10, and an outer side 20 extending to a color selecting electrode 3 side by inclining at the angle same as the deflecting angle of the electron beam from both ends of the horizontal side 19. Consequently, an external magnetic flux in the tube axial direction flowing in to the longer side side walls 9 and 10 does not pass through the center, but flows by passing through the both ends.

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 internal magnetic shield attached to a color cathode ray 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. Things.

[0002]

2. Description of the Related Art FIG. 5 is a partially cutaway perspective view showing a conventional three-electron beam type color cathode ray tube. In the figure, 1
Is a color cathode ray tube, 2 is a panel portion having a fluorescent screen formed on the inner surface of a face plate, 3 is a color selection electrode arranged in the panel portion 2 so as to face the fluorescent screen at an interval, and 4 is a color selection electrode 3. The supporting frame 5 is a funnel part having a neck part 6, and the panel part 2 is joined to an open end thereof. Reference numeral 7 denotes an electron gun mounted in the neck portion 6, and reference numeral 8 denotes an internal magnetic shield installed in the funnel portion 5 so as to surround a traveling path of an electron beam emitted from the electron gun 7. In a color cathode ray tube, the trajectory of an electron beam fluctuates under the influence of an external magnetic field such as terrestrial magnetism, and undesired results such as color misregistration are caused by emitting unwanted phosphors due to such a change in the trajectory of the electron beam. It is known to invite. In order to remove the influence of such an external magnetic field, an internal magnetic shield 8 is attached along the funnel section 5 from the color selection electrode 3.

In order to enhance the shielding performance of the internal magnetic shield 8, the shape of the opening on the electron gun side as viewed from the tube axis direction is made circular around the tube axis.
No. 657334. FIG. 6 is a plan view when the internal magnetic shield 8 is viewed from the tube axis direction, where 9 and 10 are the upper side and lower side which are the long side walls, and 11 and 12 are the right side which is the short side wall. The surface and left side surface 13 are openings on the electron gun side.

FIG. 7 shows the flow of the magnetic flux of the internal magnetic shield 8 in the tube axis direction. As is clear from FIG.
The magnetic flux 14 in the tube axis direction, which is distant from the center in the left-right direction in the vicinity of the upper surface 9 and the lower surface 10, is distributed to the right side surface 11 and the left side surface 1
2, and flows intensively at the corners of the internal magnetic shield 8. However, such a magnetic flux 14
The flow of the magnetic flux 14 does not change at the center of the upper side surface 9 and the lower side surface 10 which are the long sides of the internal magnetic shield 8, and the flow from the end of the color selection electrode of the internal magnetic shield 8 to the electron gun side The shielding performance against the external magnetic field is deteriorated by an amount corresponding to the decrease in the length to the end, and the electron beam 1
The magnetic flux 14 orthogonal to the trajectory 5 increases.

In Japanese Patent Application Laid-Open No. 7-65734,
Although the flow of the external magnetic flux 14 into the internal magnetic shield 8 is shown, no consideration is given to the flow of the magnetic flux 14 after the magnetic flux 14 flows into the internal magnetic shield 8. As a matter of fact, the magnetic flux 14 that has entered the internal magnetic shield 8 exits the internal magnetic shield 8 and flows to the color selection electrode 3 across the orbit of the electron beam 15 as shown in FIG. For this reason, a problem that the trajectory of the electron beam 15 is bent to cause a color shift occurs particularly at the center of the upper and lower sides of the screen where the magnetic resistance is high.

[0006]

As described above, the internal magnetic shield 8 of the conventional color cathode ray tube has insufficient magnetic shielding performance at the central portion on the upper and lower sides of the screen against the external magnetic field in the tube axis direction. In particular, in the case of a color cathode ray tube having a stripe-shaped fluorescent screen, the trajectory of the electron beam 15 in the vertical direction does not change, but the trajectory of the electron beam 15 in the horizontal direction causes a color shift. The flow of the magnetic flux 14 from the upper side surface 9 and the lower side surface 10 of the internal magnetic shield 8 to the color selection electrode 3 at the upper and lower central portions has a problem that the trajectory of the electron beam 15 is changed laterally to cause color shift. Was.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is intended to control the flow of external magnetic flux in the tube axis direction flowing into the long side wall of the internal magnetic shield to thereby improve the tube axis direction. It is an object of the present invention to obtain a color cathode ray tube capable of preventing a color shift at a central portion on the upper and lower sides of a screen without impairing a shielding performance against an external magnetic field.

[0008]

According to the present invention, there is provided a color cathode ray tube according to the present invention, comprising: a panel portion having a substantially rectangular face plate formed on an inner surface thereof with a stripe-shaped fluorescent surface composed of a plurality of phosphor rows parallel to the short sides thereof. A color selection electrode arranged opposite to the stripe-shaped phosphor screen at an interval, a neck portion connected to the panel portion via a funnel portion, and an electronic device mounted on the neck portion and electrically connected to the phosphor screen via the color selection electrode. A color cathode-ray tube comprising: an electron gun for irradiating a beam; and an inner magnetic shield having a substantially truncated pyramid shape extending from the color selection electrode in the direction of the electron gun and surrounding the traveling path of the electron beam. A window is provided on the side wall so that the external magnetic flux in the tube axis direction flowing into the long side wall flows through both sides of the long side wall without passing through the center.

A window provided on the long side wall has a horizontal side parallel to the electron gun side end of the long side wall, and an outside extending from both ends of the horizontal side to the color selection electrode side. It consists of sides.

Further, the outer side is inclined at substantially the same angle as the deflection angle of the electron beam.

The window provided on the long side wall has a long side along the center line in the tube axis direction of the long side wall and a short side along the color selection electrode side end. It comprises a pair of triangular windows symmetrically arranged so that the sides are located on the center line side of the long side wall, and a plurality of windows arranged in the tube axis direction between the triangular windows. .

Further, the plurality of windows arranged between the triangular windows have a rectangular shape whose long side is parallel to the end of the long side wall.

Further, a plurality of windows provided on the long side wall are arranged at least in the tube axis direction, and connect the outer shape of the long side wall apart from the center line in the tube axis direction in the tube axis direction. The pair of lines are configured to be symmetrical with respect to the center line of the long side wall away from the center line of the long side wall as going from the electron gun side end of the long side wall to the color selection electrode side end. is there.

Further, the plurality of windows are arranged in a rectangular shape whose long side is parallel to the end of the long side wall.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a partially cutaway perspective view showing a 17-inch color cathode ray tube according to Embodiment 1 of the present invention. In the figure, 1 is a color cathode ray tube, 2 is a panel portion in which a stripe-shaped phosphor screen composed of a large number of phosphor rows parallel to its short side is formed on the inner surface of a substantially rectangular face plate,
Reference numeral 3 denotes a color selection electrode which is disposed in the panel section 2 so as to face the phosphor screen at an interval, and is of a type called an aperture grill having a large number of slit-like pores. Reference numeral 4 denotes an elastic frame that applies tension to the color selection electrode 3 to support the electrode.
Is a funnel part having a neck part 6, and the panel part 2 is joined to the open end thereof. Reference numeral 7 denotes an electron gun mounted in the neck portion 6 for irradiating the phosphor screen with an electron beam through the color selection electrode 3, and 8 extends from the color selection electrode 3 in the direction of the electron gun 7 and is emitted from the electron gun 7. A substantially quadrangular pyramid-shaped internal magnetic shield installed in the funnel portion 5 so as to surround the electron beam traveling path, and a window 16 is provided on a long side wall thereof.

FIG. 2 is a side view of the long side walls 9 and 10 of the internal magnetic shield 8. The long side walls 9 and 10 have an electron gun side end 17 length L1 of 140 mm and a color selection electrode side. Edge 1
8, the length L2 is set to 279 mm, and the height H1 is set to 88 mm. Windows 16 provided on the long side walls 9 and 10
Has a length parallel to the electron gun-side end 17 of the long side walls 9 and 10 and about 60% of the length of the end 17, and the center line of the long side walls 9 and 10 in the tube axis direction. A horizontal side 19 having a center coincident with Z and an outer side 20 extending toward the color selection electrode 3 from both ends of the horizontal side 19 at an angle substantially equal to the deflection angle of the electron beam. And the width W of the window 16
Is set to 12 mm.

According to such a configuration, the long side wall 9,
As shown in FIG. 2, the flow of the magnetic flux 14 in the tube axis direction to 10, the magnetic flux 14 flowing into the central part of the long side walls 9, 10 is 9,
10 cannot flow through the central portion of the inner magnetic shield 8 and flows through both side portions having a low magnetic resistance.
It is also suppressed from flowing out. Further, since the outer side 20 of the window 16 is inclined at substantially the same angle as the deflection angle of the electron beam, the magnetic flux 14
However, even when the magnetic flux 14 is generated, the magnetic flux 14 is parallel to the electron beam, so that there is an effect that the influence on the beam trajectory is reduced. In addition, since the length from the electron gun side edge 17 to the color selection electrode side edge 18 at the center of the long side walls 9 and 10 is not reduced, the screen upper and lower center portions are maintained without impairing the shielding performance against an external magnetic field. Color misregistration can be prevented.

If the width W of the window 16 is less than 10 mm, the magnetic resistance of the window 16 is so small that the flow of the magnetic flux 14 cannot be changed. Since the performance itself deteriorates, it is desirable to set the width W of the window 16 in this range. The position and width W of the horizontal side 19 of the window 16 from the electron gun side end 17 are determined by the magnetic resistance of the space defined by the horizontal side 19 in the center line Z direction and the magnetic resistance of the horizontal side 19 other than the space. It is desirable to configure so as to be about 10 times or more.

Embodiment 2 FIG. 3 is a side view of a long side wall of the internal magnetic shield 8 which is a feature of the present invention and is used for a 17-inch color cathode ray tube according to the second embodiment of the present invention. The length L1 of the electron gun side edge 17 is set to 140 mm, the length L2 of the color selection electrode side edge 18 is set to 279 mm, and the height H1 is set to 88 mm. The long side walls 9 and 10 have the long side walls 9 and
10 has a long side along the center line Z in the tube axis direction and a short side along the color selection electrode side end 18, and is symmetrical with respect to the center line Z so that the long side is located on the center line Z side. Are provided, and three rectangular windows 22 are provided between the pair of right-angled triangular windows 21 in the tube axis direction. Each triangular window 21 has a short side length L3 of 32 mm,
The length L4 of the long side is 70 mm, and the interval L between the two triangular windows 21
5 is set to 40 mm. Each rectangular window 22
The long side is provided so as to be parallel to the end sides of the long side walls 9 and 10, the length L6 of the long side is 30 mm, the length L7 of the short side is 12 mm, and the length of the adjacent rectangular window 22 is Interval L
8 is set to 11 mm.

According to such a configuration, the long side wall 9,
As shown in FIG. 3, the flow of the magnetic flux 14 in the tube axis direction to the central axis 10, the magnetic flux 14 flowing into the central portion of the long side walls 9, 10 is formed by a triangular window 21 and a rectangular window 22. Therefore, it cannot pass through the central portion of the long side walls 9 and 10 and flows through both side portions having low magnetic resistance, so that the flow out of the internal magnetic shield 8 is also suppressed. In addition, since the triangular window 21 is symmetrically arranged with the center line Z interposed therebetween such that the long side is located on the center line Z side, the hypotenuse is inclined at substantially the same angle as the electron beam deflection angle, and the internal magnetic field is reduced. Even when the magnetic flux 14 flowing out of the shield 8 is generated, the magnetic flux 14 is parallel to the electron beam, so that the effect on the beam trajectory is reduced. Moreover,
Since the length from the electron gun side edge 17 at the central portion of the long side walls 9 and 10 to the color selection electrode side edge 18 does not decrease, the color of the upper and lower central portions of the screen without impairing the shielding performance against an external magnetic field. Shift can be prevented. Further, compared to the first embodiment, the structure is stronger, and there is an effect that the vibration when demagnetizing is performed is small, and the strength against drop and impact is large.

When the length L7 of the short side of the rectangular window 22 is 10 mm or less, the magnetic resistance of the window 22 is small and the magnetic flux 14
Can not be changed, the window 22
Is large, and the shielding performance itself of the internal magnetic shield 8 deteriorates. Therefore, it is desirable that the length L7 of the short side of the rectangular window 22 be set in this range. The window 22 provided between the pair of triangular windows 21 is not limited to a rectangle, but may be an ellipse, an oval, a square, a polygon, or the like. Can be triangular. Also,
Although the case where three rectangular windows 22 are provided is shown, the present invention is not limited to this case.
The window 22 may be provided so that the flow of the magnetic flux 14 can be controlled so that the external magnetic flux in the tube axis direction flowing into the tube flows not through the central portion of the long side walls 9 and 10 but through both side portions.

Embodiment 3 FIG. FIG. 4 is a side view of a long side wall of the internal magnetic shield 8 which is a feature of the present invention and is used for a 17-inch color cathode ray tube according to the third embodiment of the present invention. The length L1 of the electron gun side edge 17 is set to 140 mm, the length L2 of the color selection electrode side edge 18 is set to 279 mm, and the height H1 is set to 88 mm. The long side walls 9 and 10 have the long side walls 9 and
A total of six rectangular windows, one, two, and three, are sequentially arranged in three stages from the electron gun side end 17 to the color selection electrode side end 18 around the center line Z in the tube axis direction of 10. 23, a pair of lines connecting the outer shape of the rectangular window 23 of each step away from the center line Z in the tube axis direction is moved from the center line Z toward the color selection electrode side end 18 from the electron gun side end 17. It is arranged so as to be distant and symmetrical about the center line Z. Each rectangular window 23 is provided so that its long side is parallel to the end side of the long side walls 9 and 10, the length L9 of the long side is 30 mm, the length L10 of the short side is 12 mm, The distance L11 between the steps is 10 mm, the distance L12 between the third step and the edge 18 on the color selection electrode side is 16 mm, and the distance L2 from the center line Z of the rectangular window 23 on both the left and right sides of the center line Z of the second step. Distance is 27m
m, the distance from the center line Z of the rectangular window 23 on both the left and right sides across the center line Z of the third stage is set to 40 mm.

According to such a configuration, the long side wall 9,
As shown in FIG. 4, the flow of the magnetic flux 14 in the tube axis direction to 10, the magnetic flux 14 flowing into the central portion of the long side walls 9, 10 has a long side because of the rectangular window 23. It cannot pass through the central portions of the side walls 9 and 10, and flows through both side portions having a low magnetic resistance, so that the outflow from the internal magnetic shield 8 is also suppressed. In addition, a pair of lines connecting the rectangular window 23 in the tube axis direction with the outer shape away from the center line Z of the rectangular window 23 of each step is formed by an electron gun side edge 17.
Are located away from the center line Z toward the color selection electrode side edge 18 and are symmetrical with respect to the center line Z, so that a pair of lines connecting this outer shape in the tube axis direction is a deflection angle of the electron beam. When the magnetic flux 14 flowing out of the internal magnetic shield 8 is generated, the magnetic flux 1
4 is parallel to the electron beam, so that the effect on the beam trajectory is reduced. In addition, since the length from the electron gun side edge 17 to the color selection electrode side edge 18 at the center of the long side walls 9 and 10 is not reduced, the screen upper and lower center portions are maintained without impairing the shielding performance against an external magnetic field. Color misregistration can be prevented. Further, compared to the first and second embodiments, there is a portion having no space in the direction crossing the center line Z, so that there is an effect that the shielding performance against magnetic fields other than the tube axis direction is good.

The length L10 of the short side of the rectangular window 23
Is less than 10 mm, the magnetic resistance of the window 23 is small and the magnetic flux 1
4 cannot be changed, and the window 2
3, the shield performance of the internal magnetic shield 8 itself deteriorates due to a large magnetic resistance. Therefore, it is desirable to set the length L10 of the short side of the rectangular window 23 to this range. In addition, the rectangular window 23 is not limited to a rectangle, but may be an ellipse,
Oval, square, polygonal, etc. can be adopted as appropriate. In addition, although the case where the three rectangular windows 23 are arranged in three steps with six windows is shown, for example, the central window 23 of the third step may be omitted, or the windows 23 of the second and third steps may be intermediate. May be removed to form a continuous single window, and the number of windows 23 and the number of steps are not limited thereto. in short,
The window 23 is provided so that the flow of the magnetic flux 14 is controlled so that the external magnetic flux in the tube axis direction flowing into the long side walls 9 and 10 does not pass through the center of the long side walls 9 and 10 but flows through both sides. You should be able to do it.

In each embodiment, the case of the internal magnetic shield of the 17-inch color cathode ray tube has been described, but the present invention is of course effective regardless of the inch size. Also, the case where the shape of the internal magnetic shield is a truncated quadrangular pyramid has been described, but the same effect can be obtained with other shapes, for example, a dome-shaped internal magnetic shield.

[0026]

According to the color cathode ray tube of the present invention, the external magnetic flux in the tube axis direction flowing into the long side wall passes through the central portion of the long side wall on the long side wall of the internal magnetic shield. Since the windows are provided so that they flow through both sides,
It is possible to prevent a color shift at the center of the upper and lower sides of the screen without impairing the shielding performance of the internal magnetic shield.

The window provided on the long side wall has a horizontal side parallel to the electron gun side end of the long side wall, and an outside extending from both ends of the horizontal side to the color selection electrode side. Because of the sides, the flow of the external magnetic flux in the tube axis direction flowing into the long side wall of the internal magnetic shield can be effectively controlled only by providing a window having a simple configuration.

Further, since the outer side is inclined at substantially the same angle as the deflection angle of the electron beam, the magnetic flux is parallel to the electron beam even when a magnetic flux flowing out of the internal magnetic shield is generated. The effect can be reduced.

The window provided on the long side wall has a long side along the center line in the tube axis direction of the long side wall and a short side along the color selection electrode side end. It comprises a pair of triangular windows symmetrically arranged so that the sides are located on the center line side of the long side wall, and a plurality of windows arranged in the tube axis direction between the triangular windows. Therefore, it is possible to prevent color shift at the center of the upper and lower sides of the screen without impairing the structural strength and shielding performance of the internal magnetic shield, and even when magnetic flux flowing out of the internal magnetic shield occurs, the magnetic flux is parallel to the electron beam Therefore, the influence on the beam trajectory can be reduced.

Further, since the plurality of windows arranged between the triangular windows have a rectangular shape whose long side is parallel to the end of the long side wall, the direction of the tube axis flowing into the long side wall is reduced. Can be effectively controlled so that the external magnetic flux does not pass through the center of the long side wall.

Further, a plurality of windows provided on the long side wall are arranged at least in the tube axis direction, and connect the outer shape of the long side wall apart from the center line in the tube axis direction in the tube axis direction. The pair of lines are configured so as to be symmetrical with respect to the center line of the long side wall away from the center line of the long side wall as going from the electron gun side end of the long side wall to the color selection electrode side end. It is possible to prevent the color shift at the center of the upper and lower sides of the screen without impairing the shielding performance of the external magnetic flux in the tube axis direction of the internal magnetic shield, and even when the magnetic flux flowing out of the internal magnetic shield occurs, the magnetic flux is parallel to the electron beam Therefore, in addition to being able to reduce the influence on the beam trajectory, there is an effect that the shielding performance against magnetic fields other than the tube axis direction is also good.

Further, since the plurality of windows have a rectangular shape whose long side is parallel to the end of the long side wall, external magnetic flux in the tube axis direction flowing into the long side wall is reduced by the long side. It can be effectively controlled not to pass through the center of the side wall.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a color cathode ray tube according to Embodiment 1 of the present invention.

FIG. 2 is a side view showing an internal magnetic shield which is a feature of the color cathode ray tube according to the first embodiment of the present invention.

FIG. 3 is a side view showing an internal magnetic shield which is a feature of the color cathode ray tube according to the second embodiment of the present invention.

FIG. 4 is a side view showing an internal magnetic shield which is a feature of a color cathode ray tube according to Embodiment 3 of the present invention.

FIG. 5 is a partially cutaway perspective view showing a conventional color cathode ray tube.

FIG. 6 is a plan view showing an internal magnetic shield of a conventional color cathode ray tube.

FIG. 7 is a side view for explaining the operation of an internal magnetic shield of a conventional color cathode ray tube.

FIG. 8 is a side view for explaining the operation of an internal magnetic shield of a conventional color cathode ray tube.

[Explanation of symbols]

1 color cathode ray tube, 2 panel section, 3 color selection electrode, 5 funnel section, 6 neck section, 7 electron gun, 8 internal magnetic shield, 9, 10 long side wall,
11, 12 Short side wall, 14 External magnetic flux in tube axis direction, 15 Electron beam, 16 Window, 17 Electron gun side edge, 18 Color selection electrode side edge, 19 Horizontal side, 2
0 Outer side, 21 Triangular window, 22, 23 Rectangular window.

Claims (7)

[Claims] 1. A panel portion in which a stripe-shaped phosphor screen composed of a number of phosphor rows parallel to a short side thereof is formed on an inner surface of a substantially rectangular face plate, and the panel portion is opposed to the striped phosphor surface at an interval. The color selection electrode, and a neck connected to the panel unit via a funnel, an electron gun mounted in the neck and irradiating the phosphor screen with an electron beam through the color selection electrode, In a color cathode ray tube having a substantially quadrangular truncated pyramid-shaped internal magnetic shield extending from the color selection electrode in the direction of the electron gun and surrounding the electron beam traveling path, the long side wall of the internal magnetic shield is A color cathode ray tube having a window provided so that an external magnetic flux in a tube axis direction flowing into a long side wall flows through both sides of the long side wall without passing through a central portion of the long side wall. 2. A window provided on the long side wall includes a horizontal side parallel to the electron gun side end of the long side wall, and an outer side extending from both ends of the horizontal side to the color selection electrode side. 2. The color cathode ray tube according to claim 1, wherein the color cathode ray tube comprises sides. 3. The color cathode ray tube according to claim 2, wherein the outer side is inclined at substantially the same angle as the electron beam deflection angle. 4. The window provided on the long side wall has a long side along the center line in the tube axis direction of the long side wall and a short side along the color selection electrode side end. A pair of triangular windows arranged symmetrically so that the long sides are located on the center line side of the long side wall, and a plurality of windows arranged in the tube axis direction between the triangular windows. The color cathode ray tube according to claim 1, wherein: 5. The color cathode ray tube according to claim 4, wherein the plurality of windows arranged between the triangular windows have a rectangular shape whose long side is parallel to an end of the long side wall. . 6. A plurality of windows provided on the long side wall at least in the tube axis direction, and the outer shape of the long side wall apart from the center line of the long side wall in the tube axis direction is set in the tube axis direction. Are arranged away from the center line of the long side wall as going from the electron gun side end of the long side wall to the color selection electrode side end of the long side wall and become symmetrical with respect to the center line. 2. The color cathode ray tube according to claim 1, wherein the color cathode ray tube is formed. 7. The color cathode ray tube according to claim 6, wherein the plurality of windows have a rectangular shape whose long side is parallel to an end of the long side wall.