Information
-
Patent Grant
-
6791287
-
Patent Number
6,791,287
-
Date Filed
Monday, September 30, 200222 years ago
-
Date Issued
Tuesday, September 14, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 315 364
- 315 370
- 315 36811
- 315 399
- 315 400
- 313 412
- 313 413
- 313 409
- 313 421
- 313 428
- 313 431
- 313 442
- 313 440
- 335 210
- 335 212
- 335 213
-
International Classifications
-
Abstract
A deflection yoke device includes a deflection yoke for deflecting electron beams in horizontal and vertical directions, the electron beams being emitted from an electron gun of a color cathode ray tube; coma correcting coils positioned on an electron gun side of the deflection yoke so as to be opposed to each other in such a manner that the electron beams pass therebetween; and a pair of cores around which the coma correcting coils are wound, wherein a sliding mechanism is further provided for allowing each of the coma correcting coils to be slidable with respect to the corresponding core. Therefore, a misconvergence can be corrected by a simplified configuration without reducing a sensitivity of the coma correcting coils.
Description
TECHNICAL FIELD
The present invention relates to a deflection yoke device for use in a color cathode ray tube of a television receiver, a computer display or the like.
BACKGROUND ART
Generally, convergence properties are affected by a shift of a central axis of a deflection yoke device from a central axis of a color cathode ray tube or a so-called deflection yoke tilt such that the central axes cross each other at a certain angle. As a solution to this, the following technique has been disclosed in JP 11 (1999)-54067 A.
As shown in
FIG. 8
, a deflection yoke device
1
is provided with a deflection yoke
3
having a configuration in which horizontal and vertical deflection coils
2
for detecting electron beams emitted from an electron gun of a color cathode ray tube in a horizontal direction and in a vertical direction, respectively, are positioned on an insulation frame
21
. A pair of U-shaped cores
4
a
and
4
b
are positioned on the electron gun side of the deflection yoke
3
so as to be opposed to each other with a path of the electron beams interposed therebetween, and quadrupole coma correcting coils
5
a
and
5
b
are wound around the U-shaped cores
4
a
and
4
b
, respectively. The U-shaped cores
4
a
and
4
b
are slidable in a vertical direction or in a lateral direction by a sliding mechanism (not shown).
According to this configuration, when a central axis shift in a vertical direction between the color cathode ray tube and the deflection yoke
3
causes a Y
H
misconvergence as shown in
FIG. 9A
, the pair of U-shaped cores
4
a
and
4
b
provided with the coma correcting coils
5
a
and
5
b
are slid in a vertical direction as shown by an arrow in FIG.
10
A. This allows the Y
H
misconvergence due to the central axis shift between the color cathode ray tube and the deflection yoke
3
to be corrected without tilting the deflection yoke
3
. Further, when a central axis shift in a lateral direction between the color cathode ray tube and the deflection yoke
3
causes a Y
V
misconvergence as shown in
FIG. 9B
, the pair of U-shaped cores
4
a
and
4
b
provided with the coma correcting coils
5
a
and
5
b
are slid in a horizontal direction as shown by an arrow in FIG.
10
B. This allows the Y
V
misconvergence due to the central axis shift between the color cathode ray tube and the deflection yoke
3
to be corrected without tilting the deflection yoke
3
.
However, in order to correct the misconvergence, the above-mentioned configuration requires a space or sliding mechanisms for allowing the U-shaped cores
4
a
and
4
b
to be slidable in a vertical direction or in a lateral direction from positions shown by solid lines to positions shown by dashed lines as shown in
FIGS. 10A and 10B
. Consequently, there is a possibility that a distance from the electron beams to each end of the U-shaped cores
4
a
and
4
b
might increase undesirably, which causes a reduction of sensitivity (efficiency) of the coma correcting coils
5
a
and
5
b
. Further, it is necessary to employ a mechanical component for allowing the U-shaped cores
4
a
and
4
b
to be slidable, which results in a complicated configuration.
DISCLOSURE OF THE INVENTION
Therefore, with the foregoing in mind, it is an object of the present invention to provide a deflection yoke device that can correct a misconvergence with a simplified configuration without reducing a sensitivity of coma correcting coils.
The deflection yoke device of the present invention includes: a deflection yoke for deflecting electron beams in a horizontal direction and in a vertical direction, the electron beams being emitted from an electron gun of a color cathode ray tube; coma correcting coils positioned on an electron gun side of the deflection yoke so as to be opposed to each other in such a manner that the electron beams pass therebetween; and a pair of cores around which the coma correcting coils are wound. In the deflection yoke device, a sliding mechanism further is provided for sliding each of the coma correcting coils with respect to the corresponding core.
According to the above-mentioned configuration, ends of the cores can be positioned in contact with or in close proximity to a neck portion of the color cathode ray tube, thereby preventing a reduction of sensitivity of the coma correcting coils. Further, it is required for the configuration only to make the coma correcting coils slidable with respect to the cores, which eliminates the need for an additional mechanical component for sliding the cores as in the prior art.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1
is a cross-sectional view of a color cathode ray tube provided with a deflection yoke device according to a first embodiment of the present invention.
FIG. 2
is a perspective side view of the deflection yoke device.
FIG. 3
is a rear elevation of the deflection yoke device.
FIG. 4
is a view showing magnetic lines of force after sliding of bobbins of quadrupole coma correcting coils in the deflection yoke device.
FIG. 5
is a rear elevation of a deflection yoke device according to a second embodiment of the present invention.
FIG. 6
is a rear elevation of a deflection yoke device according to a third embodiment of the present invention.
FIG. 7A
is a rear elevation of a part of a deflection yoke device according to a fourth embodiment of the present invention.
FIG. 7B
is a rear elevation showing an operation of the same deflection yoke device.
FIG. 8
is a perspective side view of a conventional deflection yoke device.
FIGS. 9A
to
9
D are views showing misconvergence patterns.
FIGS. 10A and 10B
are rear elevations showing operations of the conventional deflection yoke device.
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described by way of embodiments with reference to the appended drawings.
First Embodiment
FIG. 1
shows a color cathode ray tube
9
provided with a deflection yoke device
10
according to an embodiment of the present invention. The color cathode ray tube
9
is composed of a panel
11
having a phosphor screen
11
a
, a frame
13
having a shadow mask
12
located at a position opposed to the phosphor screen
11
a
, a neck tube portion
14
a
having an electron gun
15
thereinside, and a funnel portion
14
establishing a connection between the neck tube portion
14
a
and the panel
11
. For convenience in the following description, as shown in the figures, a horizontal direction (actually, a direction orthogonal to a sheet surface of the figure) is referred to as a lateral direction and a top-to-bottom direction is referred to as a vertical direction.
The deflection yoke device
10
is provided on an outer surface of the funnel portion
14
for deflecting electron beams
15
R,
15
G and
15
B emitted from the electron gun
15
. As shown in
FIGS. 2 and 3
, the deflection yoke device
10
is provided with a deflection yoke
3
, a pair of U-shaped cores
17
a
and
17
b
and sliding mechanisms
19
. The deflection yoke
3
has horizontal and vertical deflection coils
2
provided in a pair, respectively, for generating a magnetic field so as to deflect the electron beams
15
R,
15
G and
15
B emitted from the electron gun
15
in horizontal and vertical directions. The U-shaped cores
17
a
and
17
b
are positioned to be opposed to each other on the electron gun side of the deflection yoke
3
with the electron beams
15
R,
15
G and
15
B interposed therebetween, and further, quadrupole coma correcting coils
18
a
and
18
b
are wound around the U-shaped cores at bottoms of the U shapes. The sliding mechanisms
19
allow the coma correcting coils
18
a
and
18
b
to be slidable with respect to the U-shaped cores
17
a
and
17
b
. The coma correcting coils
18
a
and
18
b
are connected in series to the vertical deflection coil
2
.
An insulation frame
21
of the deflection yoke
3
includes a wall
21
a
having a shape of a conical frustum on which the horizontal and vertical deflection coils
2
are provided, and a core attachment plate portion
21
b
positioned on the smaller diameter side of the wall
21
a
, the core attachment plate portion
21
b
being integrated with the wall
21
a
. On the core attachment plate portion
21
b
, a projected portion
21
c
is formed. The core attachment plate portion
21
b
is not necessarily integrated with the wall
21
a
, and it may be provided separately from the insulation frame
21
as an individual member.
The U-shaped cores
17
a
and
17
b
are fixed to the projected portion
21
c
of the core attachment plate portion
21
b
. The coma correcting coils
18
a
and
18
b
are wound around tubular-shaped bobbins
20
a
and
20
b
as shown in FIG.
3
. The bobbins
20
a
and
20
b
have inside diameters larger than outside diameters of the U-shaped cores
17
a
and
17
b
, so that the bobbins
20
a
and
20
b
can slide in a lateral direction on intermediate portions S of the U-shaped cores
17
a
and
17
b
, thus defining the sliding mechanisms
19
. Thus, this configuration enables the correction of a VG crossed misconvergence shown in
FIG. 9C
due to a rotational shift of the deflection yoke
3
with respect to the color cathode ray tube in addition to the correction of the Y
V
misconvergence shown in
FIG. 9B
, which is described in the above “BACKGROUND ART”. After the misconvergences are corrected, the bobbins
20
a
and
20
b
are fixed to the U-shaped cores
17
a
and
17
b
using a hot-melt adhesive.
It is preferable that the inside diameters of the bobbins
20
a
and
20
b
, and the outside diameters of the U-shaped cores
17
a
and
17
b
are set to dimensions such that their positions relative to each other can be fixed by friction. More specifically, it is preferable that the U-shaped cores are fitted in the bobbins in such a manner that positions of the bobbins
20
a
and
20
b
do not shift unless an external force larger than a certain set level is applied thereto. As an example of dimensions for realizing this, when the inside diameters of the bobbins
20
a
and
20
b
are set to 6 mm minus 0 to 0.2 mm and the outside diameters of the U-shaped cores
17
a
and
17
b
are set to 6 mm minus 0.05 to 0 mm, a good result can be obtained.
Before fixing the bobbins
20
a
and
20
b
to the U-shaped cores
17
a
and
17
b
using an adhesive, the bobbins
20
a
and
20
b
are fixed temporarily to the midsections of the U-shaped cores
17
a
and
17
b
. When a correction is required, positions of the bobbins
20
a
and
20
b
are corrected manually. Finally, the bobbins
20
a
and
20
b
are fixed to the U-shaped cores
17
a
and
17
b
using the adhesive irrespective of whether the position correction was carried out.
A length L
1
of the intermediate portion S of each of the U-shaped cores
17
a
and
17
b
is larger than a coil-wound length L
2
of each of the bobbins
20
a
and
20
b
. Further, the U-shaped cores
17
a
and
17
b
are arranged so that the ends thereof are in contact with or in close proximity to an outer circumferential surface of the neck tube portion
14
a.
Functions and effects of the deflection yoke device configured as mentioned above will be described below.
Since the deflection yoke device
10
of the present invention is provided with the sliding mechanisms
19
that allow the coma correcting coils
18
a
and
18
b
to be slidable in a lateral direction on the U-shaped cores
17
a
and
17
b
, magnetic fields generated from both the ends of the U-shaped cores
17
a
and
17
b
can be asymmetric as shown in FIG.
4
. Accordingly, as mentioned above, the VG crossed misconvergence shown in
FIG. 9C
also can be corrected in addition to the correction of the Y
V
misconvergence shown in FIG.
9
B. Consequently, an optimum image can be obtained.
The magnetic fields generated from both the ends of the U-shaped core
17
a
(
17
b
) become asymmetric for the following reasons. The first reason is that there is a difference between respective distances from the coma correcting coil
18
a
(
18
b
) to left and right ends of the core
17
a
(
17
b
), which causes a difference in strength between the magnetic fields generated from the left and right ends of the core
17
a
(
17
b
). The second reason is that since a position of the coma correcting coil
18
a
(
18
b
) shifts from the center of the U-shaped core
17
a
(
17
b
) to the left or the right, the electron beams are affected asymmetrically by a radiational magnetic field that is applied directly from the coma correcting coil
18
a
(
18
b
) itself.
In the deflection yoke device
10
of the present invention, the U-shaped cores
17
a
and
17
b
are fixed to the core attachment plate portion
21
b
with both the ends being in contact with or in close proximity to the neck tube portion
14
a
, and positions of the ends of the U-shaped cores
17
a
and
17
b
of the present invention do not change, unlike the prior art shown in
FIGS. 10A and 10B
, in which positions of ends of U-shaped cores
4
a
and
4
b
change with respect to a neck portion. Accordingly, the present invention can avoid a reduction of sensitivity of the coma correcting coils
18
a
and
18
b
due to the change in the positions of both the ends of the U-shaped cores.
Further, since the deflection yoke device
10
of the present invention is configured only by making the bobbins
20
a
and
20
b
slidable in a lateral direction with respect to the U-shaped cores
17
a
and
17
b
, it does not require any additional mechanical component that the prior art requires for making the U-shaped cores
4
a
and
4
b
slidable. Consequently, the configuration can be simplified as compared with the prior art, and further a space for attaching the U-shaped cores
17
a
and
17
b
to the core attachment plate portion
21
b
can be reduced.
The following is an explanation of experiments for confirming effects with regard to a correction amount of the VG crossed misconvergence that occurred when the yoke deflection device
10
of the present invention shown in
FIGS. 2 and 3
was fitted to the color cathode ray tube as shown in
FIG. 1
, and the bobbins
20
a
and
20
b
were slid in a lateral direction to the U-shaped cores
17
a
and
17
b.
As the color cathode ray tube
9
, a 46 (cm) cathode ray tube for a computer monitor was employed. Each of the U-shaped cores
17
a
and
17
b
had a width B of 6 mm, and the intermediate portion S thereof had a length L
1
of 20 mm. Each of the bobbins
20
a
and
20
b
had a coil-wound length L
2
of 14 mm and a winding number of 80 turns.
The above-mentioned correction amount is defined as a distance E shown in
FIG. 9C
that corresponds to a lateral movement of the electron beams in a peripheral portion of the panel, which is caused by a slide displacement of the bobbins
20
a
and
20
b
from the center Y either to the left or the right as shown in FIG.
3
.
The experimental results show that when the bobbins
20
a
and
20
b
were slid from the center Y either to the left or the right by a distance of 20% of the coil winding length L
2
in the deflection yoke device of the present invention, there was a change in the distance E by 0.1 mm.
The sliding mechanisms
19
of the present embodiment are described regarding the case where the bobbins
20
a
and
20
b
are configured to be slidable in a lateral direction with respect to the intermediate portions S of the U-shaped cores
17
a
and
17
b
. However, the configuration is not limited to this and the same effects can be obtained in another configuration. For example, the following configuration may be employed. Tubular-shaped bobbins around which coma correcting coils are wound are provided on the U-shaped cores
17
a
and
17
b
at each leg portion thereof. The inside diameters of the bobbins are made larger than the outside diameters of the U-shaped cores
17
a
and
17
b
so that the bobbins are slidable in a vertical direction on the leg portions of the U-shaped cores
17
a
and
17
b
. This configuration can realize the correction of the Y
H
misconvergence shown in
FIG. 9A
due to a central axis shift in a vertical direction between the color cathode ray tube and the deflection yoke
3
.
Second Embodiment
A deflection yoke device of a second embodiment will be described with reference to FIG.
5
. The first embodiment exemplifies a configuration in which each of the cores
17
a
and
17
b
is formed in a U shape, and the pair of the cores
17
a
and
17
b
are arranged vertically. The configuration is not limited thereto. More specifically, the shape and the position of the core can be changed as required depending on misconvergence patterns.
For example, a configuration shown in
FIG. 5
is employed so as to correct a VCR misconvergence shown in
FIG. 9D
due to a central axis shift in a vertical direction between the color cathode ray tube and the deflection yoke
3
. In this configuration, a pair of E-shaped cores
30
a
and
30
b
are arranged laterally, and bobbins
32
a
and
32
b
around which coma correcting coils
31
a
and
31
b
are wound, respectively, are fitted to the E-shaped cores
30
a
and
30
b
, respectively, at each leg portion thereof. By sliding the bobbins
32
a
and
32
b
in a lateral direction, the VCR misconvergence can be reduced.
Third Embodiment
A deflection yoke device of a third embodiment will be described with reference to
FIG. 6. A
configuration of the present embodiment is employed for correcting the Y
V
misconvergence shown in FIG.
9
B. As shown in
FIG. 6
, a pair of I-shaped cores
40
a
and
40
b
are arranged laterally, and bobbins
42
a
and
42
b
around which coma correcting coils
41
a
and
41
b
are wound, respectively, are fitted to the I-shaped cores
40
a
and
40
b
, respectively, at each rod-shaped portion thereof. By sliding the bobbins
42
a
and
42
b
in a lateral direction, the Y
V
misconvergence can be reduced.
Fourth Embodiment
A part of the deflection yoke device of the third embodiment is shown in
FIGS. 7A and 7B
. In the present embodiment, the inside diameter of the bobbin
20
a
(shown by dashed lines) is set to be larger sufficiently than the outside diameter of the U-shaped core
17
a
(shown by dashed lines) as shown in FIG.
7
A. Therefore, the coma correcting coil
18
a
is not only slidable, that is, movable parallel, but also movable rotatably with respect to the U-shaped core
17
a
as shown in FIG.
7
B. More specifically, the coma correcting coil
18
a
is slidable in an axis direction of the U-shaped core
17
a
, and also is movable rotatably in such a manner that its angle with respect to the axis of the U-shaped core
17
a
varies. This configuration causes a magnetic field to be asymmetric. For example, when the coma correcting coil
18
a
is positioned at a center of the U-shaped core
17
a
and then only moves rotatably, it is possible to obtain an asymmetric influence of a radiational magnetic field generated from the coma correcting coil
18
a.
In order to obtain a good result by the above-mentioned rotational movement, dimensions should be set so that the U-shaped core
17
a
, that is, the coma correcting coil
18
a
is movable rotatably in a range from 5° to 45°. As an example of the dimension for realizing this, the inside diameter of the bobbin
20
a
may be 13 mm and the outside diameter of the U-shaped core
17
a
may be 6 mm.
According to the present embodiment, since there is a large space between the U-shaped core
17
a
and the bobbin
20
a
, a position of the coma correcting coil
18
a
is not determined until the coma correcting coil
18
a
is fixed using an adhesive. Therefore, it is preferable to appropriately specify a height of the projected portion
21
c
from the core attachment plate portion
21
b
shown in
FIG. 2
so that the bobbin
20
a
is clamped between the core attachment plate portion
21
b
and the U-shaped core
17
a
with an appropriate force. This allows the coma correcting coil
18
a
to be fixed temporarily and also facilitates the position correction.
The coma correcting coils
18
a
,
18
b
,
31
a
,
31
b
,
41
a
and
41
b
described in the above-mentioned embodiments are connected in series to the vertical deflection coil
2
. However, those coils are not necessarily connected thereto. For example, in the case where those coils are connected in series to the horizontal deflection coil, the misconvergence can be corrected as well.
INDUSTRIAL APPLICABILITY
According to the present invention, it is possible to provide a deflection yoke device that can correct a misconvergence with a simplified configuration without reducing a sensitivity of a coma correcting coil. Therefore, when the deflection yoke device is fitted to a cathode ray tube, an optimum image can be obtained.
Claims
- 1. A deflection yoke device comprising:a deflection yoke for deflecting electron beams in horizontal and vertical directions, the electron beams being emitted from an electron gun of a color cathode ray tube; coma correcting coils positioned on an electron gun side of the deflection yoke so as to be opposed to each other in such a manner that the electron beams pass therebetween; and a pair of cores around which the coma correcting coils are wound, wherein each of the cores is formed in a shape of U, the comma correcting coils are wound around respective tubular shaped bobbins and are positioned at bottom portions or both leg portions of the U-shaped cores, and the inside diameters of the bobbins and the outside diameters of the U-shaped cores are set to dimensions such that their positions relative to each other can be fixed by friction allowing each of the bobbins to be slidable with respect to the corresponding core and to maintain the relative positions of the bobbins with only the friction force.
- 2. The deflection yoke device according to claim 1, wherein the pair of cores are arranged in a vertical direction or in a lateral direction with respect to the color cathode ray tube.
- 3. A deflection yoke device comprising:a deflection yoke for deflecting electron beams in horizontal and vertical directions, the electron beams being emitted from an electron gun of a color cathode ray tube; coma correcting coils positioned on an electron gun side of the deflection yoke so as to be opposed to each other in such a manner that the electron beams pass therebetween; and a pair of cores around which the coma correcting coils are wound, wherein each of the cores is formed in a shape of U, the coma correcting coils are positioned at bottom portions or both leg portions of the U-shaped cores, and a sliding mechanism is provided for allowing each of the coma correcting coils to be slidable in an axis direction of the core, and to be movable rotatably in a direction such that an angle of the coma correcting coil with respect to the axis of the core varies.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| 2001-019553 |
Jan 2001 |
JP |
|
PCT Information
| Filing Document |
Filing Date |
Country |
Kind |
| PCT/JP02/00580 |
|
WO |
00 |
| Publishing Document |
Publishing Date |
Country |
Kind |
| WO02/06179 |
8/8/2002 |
WO |
A |
US Referenced Citations (8)
Foreign Referenced Citations (6)
| Number |
Date |
Country |
| 7-326304 |
Dec 1995 |
JP |
| 10-50237 |
Feb 1998 |
JP |
| 4-80192 |
Jul 1998 |
JP |
| 11-54067 |
Feb 1999 |
JP |
| 11-213915 |
Aug 1999 |
JP |
| 263592 |
Nov 1995 |
TW |
