Electric lamp and discharge devices: systems – Cathode ray tube circuits – Cathode-ray deflections circuits
Reexamination Certificate
2001-09-14
2002-12-31
Philogene, Haissa (Department: 2821)
Electric lamp and discharge devices: systems
Cathode ray tube circuits
Cathode-ray deflections circuits
C315S399000, C315S370000, C315S368270, C315S368110
Reexamination Certificate
active
06501238
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a deflection yoke. In particular, the present invention relates to an apparatus for correcting mis-convergence and geometric distortion in a deflection yoke using a variable resistance in order to have a better control on VCR properties of a product by controlling current in a comma-free state, which is regarded very distinctive from the typical method of attaching a iron plate to a product.
2. Description of the Prior Art
In general, a deflection yoke
10
, as shown in
FIG. 1
, is installed at a neck portion
110
of a cathode-ray tube
100
. According to a winding configuration, it is divided into a saddle-saddle type defection yoke as shown in
FIGS. 2 and 3
, and a saddle-toroidal type deflection yoke as shown in
FIGS. 4 and 5
. The deflection yoke deflects electron beams emitted from a BGR electron gun
120
installed at the cathode-ray tube in a neck portion
110
to all directions, e.g., the left and right sides, and up and down, thereby making the electron beams collide with a precise position on a fluorescent screen of the cathode-ray tube.
FIGS. 2 and 3
show a saddle-saddle type deflection yoke in accordance with the related art. As shown in the Figures, a saddle type horizontal deflection coil
12
a
and
12
b
is installed at the top/bottom of inner periphery of screen portion in a conical-shaped coil separator
11
, and a saddle type vertical deflection coil
13
a
and
13
b
on the left/right of outer periphery. Electrically, the saddle type deflection coils are serially connected in the order of upper left
13
a
-
1
, lower left
13
a
-
2
, upper right
13
b
-
1
, and lower right
13
b
-
2
(See FIG.
6
).
In order to enhance a magnetic field of the vertical deflection coils
13
a
and
13
b
, a conical ferrite core
14
is installed at the outer periphery of the screen portion in the coil separator
11
. Also, comma-free coil
15
are installed around the outer periphery of a neck portion in the coil separator
11
to improve comma aberration generated by the vertical deflection coils
13
a
and
13
b.
FIGS. 4 and 5
show a saddle-toroidal type deflection yoke according to the related art. As shown in the figures, a horizontal deflection coil
12
is installed at the upper/lower portion of a inner periphery of a screen in a conical coil separator
11
, a conical ferrite core
14
is installed at the outer periphery, and a toroidal type vertical deflection coil
16
is wound around the upper/lower portion of the ferrite core
14
.
In addition, around the outer periphery of the neck portion of the coil separator
11
, comma-free coils
15
are additionally installed in order to improve a comma aberration generated by the vertical deflection coil
16
. The vertical deflection coil
16
is wound around the upper/lower portion of the ferrite core
14
.
In case of a saddle-saddle type deflection yoke illustrated in
FIGS. 2 and 3
, depending on the relative dispersion and/or relative current intensity between the left vertical deflection coil
13
a
and the right deflection coil
13
b
, a magnetic field may differ on the left side and the right side. This difference in a magnetic field is main factor that causes mis-convergence and geometric distortion (hereinafter, it is abbreviated as G/D).
Similarly, a saddle-toroidal deflection yoke illustrated in
FIGS. 4 and 5
, depending on the relative dispersion and/or relative current intensity between the vertical defection coil
16
a
being wound around the upper left and lower left portion in X and Y-axes and the vertical deflection coil
16
b
being wound around the upper right and lower right portion, a magnetic field may (differ on the left side and the right side. Again, this difference in a magnetic field causes mis-convergence and G/D on the screen.
There are two types of the mis-convergence, that is, YV mis-convergence and YHC mis-convergence. The YV mis-convergence, as shown in
FIGS. 7 and 9
, indicates a point where a red horizontal line R crosses a blue horizontal line B at the upper and lower portions of Y-axis on a screen. In the meantime, the YHC mis-convergence, as shown in
FIG. 10
, indicates a point where a vertical line R and a vertical line B meets each other. The G/D is a state that a screen is distorted from a normal shape (See
FIGS. 6
a
and
13
), and in particular, as
FIGS. 11 and 13
illustrate, it sometimes does a trapezoid distortion.
FIG. 14
is an auxiliary circuit of YV mis-convergence of the saddle-saddle type deflection yoke illustrated in
FIGS. 2 and 3
. As shown in the figure, the left vertical deflection coil
13
a
and the right deflection coil
13
b
are electrically connected in series. And, to the left/right vertical deflection coils
13
a
and
13
b
, connected in parallel is a differential type of distribution circuit comprising two-fixed resistance
21
a
and
21
b
and a variable resistance
22
.
According to the conventional YV mis-convergence auxiliary circuit in
FIG. 14
, by adjusting the variable resistance
22
and a magnetic field, which is generated by adjusting relative current intensity in the left vertical deflection coil
13
a
and the right vertical deflection coil
13
b
, YV mis-convergence illustrated in
FIG. 7
or
9
is corrected as shown in
FIG. 8
, wherein the line R and the line B are concordant.
FIG. 15
is an auxiliary circuit of YV mis-convergence of the saddle-toroidal type deflection yoke illustrated in
FIGS. 4 and 3
b
. As shown, the upper left vertical deflection coil
16
a
-
1
, the lower left vertical deflection coil
16
b
-
1
, the upper right vertical deflection coil
16
a
-
2
, and the lower right vertical deflection coil
16
b
-
2
are serially connected in order. And, to the vertical deflection coils
16
a
-
1
and
16
b
-
1
wound around the upper left-lower left portion and the vertical deflection coils
16
a
-
2
and
16
b
-
2
wound around the upper right-lower right portion, connected in parallel is a differential type of distribution circuit comprised of two-fixed resistance
21
a
and
21
b
and a variable resistance
22
.
Similar to the YV mis-convergence auxiliary circuit illustrated in
FIG. 14
, the conventional YV mis-convergence auxiliary circuit in
FIG. 15
, by adjusting the variable resistance
22
and a magnetic field of the left/right portion, which is generated by adjusting relative current intensity flowing in the vertical deflection coils
16
a
-
1
and
16
b
-
1
wound around the upper left and lower left portions and the vertical deflection coils
16
a
-
2
and
16
b
-
2
wound around the upper right and lower right portions, corrects the YV mis-convergence illustrated in
FIG. 7
or
9
to be the same with that in
FIG. 8
, that is, the line R and the line B are concordant.
However, in case of a saddle-saddle type and/or a saddle-toroidal type, when YV mis-convergence is corrected by using the variable resistance
22
, G/D pattern as well as convergence pattern are changed depending on the differences between the left/right portion magnetic field due to the changes in the relative current intensity flowing in the vertical deflection coil
13
a
or
16
a
positioned on the left portion and the vertical deflection coil
13
b
or
16
a
positioned on the right portion. Therefore, it is always possible that a new G/D is generated even though YV mis-convergence may have been corrected.
Moreover, G/D can be generated by dispersion difference of the left and the right vertical deflection coils that sometimes occurs during winding. That is, due to the unbalanced wound coil and dispersion difference by a mechanical configuration, it is practically very difficult to wind the coils around
1
through
4
upper portions in X and Y-axes to form a perfectly symmetric magnetic field. Hence, although a mis-convergence shown in
FIG. 5
caused by the unbalanced dispersion may have been perfectly corrected, G/D illustrated in
FIG. 11
or
13
can be generated. And, as shown in
FIG. 12
, although G/D can be perfectly corrected, a mis-converg
Choe Hwan Seok
Lim Sung Yong
Park Jin Young
Philogene Haissa
Samsung Electro-Mechanics Co. Ltd.
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