Electricity: magnetically operated switches – magnets – and electr – Magnets and electromagnets – Electron or ion beam deflecting type
Reexamination Certificate
1999-06-24
2001-03-06
Donovan, Lincoln (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Magnets and electromagnets
Electron or ion beam deflecting type
C313S440000
Reexamination Certificate
active
06198368
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a deflection yoke, and more particularly, the present invention relates to a deflection yoke which improves picture dispersion due to assembling dispersion of a vertical deflecting coil and improves winding structures of the vertical deflecting coil and a horizontal deflecting coil.
2. Description of the Related Art
Generally, a deflection yoke used in a cathode ray tube (CRT) of a television receiver or a monitor is divided into a saddle-toroid type deflection yoke and a saddle-saddle type deflection yoke and functions to precisely deflect electron beams emitted from electron guns onto a fluorescent layer applied on a screen of a cathode ray tube.
In other words, as shown in
FIG. 1
, the conventional deflection yoke
10
is fitted around a neck part
2
of a cathode ray tube
1
. As described above, the deflection yoke
10
is divided into a saddle-saddle type deflection yoke as shown in
FIGS. 2 and 3
and a saddle-toroid type deflection yoke as shown in
FIGS. 4 and 5
, depending upon a winding structure of a coil thereof.
The deflection yoke
10
serves to horizontally and vertically deflect electron beams emitted from BGR electron guns
3
which are disposed in the neck part
2
of the cathode ray tube
1
, thereby to precisely focus the electron beams onto a fluorescent layer of the cathode ray tube
1
.
FIGS. 2 and 3
illustrate the conventional saddle-saddle type deflection yoke. As can be seen from
FIGS. 2 and 3
, in the saddle-saddle type deflection yoke, horizontal deflection coils
12
having a saddle-shaped configuration are disposed on upper and lower portions of a circumferential inner surface of a screen part of a coil separator
11
having a substantially frusto-conical configuration, and vertical deflecting coils
13
having a saddle-shaped configuration are disposed on left and right portions of a circumferential outer surface of the screen part of the coil separator
11
.
A ferrite core
14
having a substantially cylindrical configuration is placed on the circumferential outer surface of the screen part of the coil separator
11
, to reinforce a magnetic field of the vertical deflecting coils
13
.
Also, coma-free coils
15
are arranged adjacent the circumference of the neck part of the coil separator
11
, to compensate for coma which is generated by the vertical deflecting coils
13
.
FIGS. 4 and 5
illustrate the conventional saddle-toroid type deflection yoke. As can be seen from
FIGS. 4 and 5
, in the saddle-toroid type deflection yoke, horizontal deflection coils
12
are disposed on upper and lower portions of a circumferential inner surface of a screen part of a coil separator
11
having a substantially frusto-conical configuration, a ferrite core
14
having a substantially cylindrical configuration is placed on a circumferential outer surface of the screen part of the coil separator
11
, and vertical deflecting coils
16
having a toroid-shaped configuration are disposed on upper and lower portions of the ferrite core
14
.
Further, coma-free coils
15
are additionally arranged adjacent the circumference of the neck part of the coil separator
11
, to compensate for coma which is generated by the vertical deflecting coils
16
.
Moreover, in the saddle-saddle type deflection yoke and the saddle-toroid type deflection yoke, a printed circuit board is positioned on a side of the coil separator
11
, to supply power to the horizontal deflecting coils
12
and the vertical deflecting coils
13
and
16
.
However, the conventional deflection yokes suffer from defects as described below.
In other words, in the process of coupling the ferrite core
14
around which the vertical deflecting coils
13
are wound, onto the circumferential outer surface of the coil separator
11
which has the horizontal deflecting coils
12
mounted onto the circumferential inner surface thereof, using a core clamp (not shown), the ferrite core
14
may be fluctuated due to its dimensional dispersion, winding dispersion of the vertical deflecting coil
13
, etc. That is to say, the ferrite core
14
may be fluctuated on the coil separator
11
in a transverse or longitudinal direction even by a light impact.
As described above, if the ferrite core
14
around which the vertical deflecting coils
13
are wound, is fluctuated on the coil separator
11
, because the vertical deflecting coils
13
cannot be precisely concentrically aligned with the coil separator
11
, stable axial balance may not be ensured, whereby distortion is caused on a picture.
Namely, in the saddle-saddle type deflection yoke, there is caused a difference between the left magnetic field and the right magnetic field, due to relative dispersion and/or relative current amount between the left vertical deflecting coils and the right vertical deflecting coils, whereby mis-convergence and geometrical distortion (G/D) are generated on a picture.
Similarly to this, also in the saddle-toroid type deflection yoke, there is caused a difference between the left magnetic field and the right magnetic field, due to relative dispersion and/or relative current amount between the vertical deflecting coils
16
disposed on left upper and lower portions of the ferrite core
14
and the vertical deflecting coils
16
disposed on right upper and lower portions of the ferrite core
14
, on X-Y axes, whereby mis-convergence and geometrical distortion (G/D) are generated on a picture.
The mis-convergence is divided into YV mis-convergence and YHC mis-convergence. The YV mis-convergence represents a vertical mis-convergence in which a transverse line of red color R is not in line with a transverse line of blue color B on upper and lower portions of Y axis as shown in
FIGS. 6 and 7
, and the YHC mis-convergence represents a horizontal misconvergence in which a longitudinal line of red color R is crossed with a longitudinal line of blue color B as shown in FIG.
8
.
The geometrical distortion (G/D) represents a state in which a picture is not normal but distorted as shown in
FIGS. 9 and 10
which specifically illustrate trapezoidal distortion of a picture.
In order to solve the problems occurring in the related art, as shown in
FIG. 11
, a plurality of elastic wedges
20
which are made of sponge, are attached on the circumferential outer surface of the coil separator
11
such that they are uniformly spaced apart one from another in a circumferential direction, to elastically bias outward the ferrite core
14
which is placed on the circumferential outer surface of the coil separator
11
, whereby assembling dispersion is reduced to overcome the defects described with reference to
FIGS. 2 through 10
.
However, in the method for maintaining axial balance of the vertical deflecting coils
13
using the plurality of elastic wedges
20
, because the elastic wedges
20
are deformed by themselves to a great extent, high dimensional precision cannot be accomplished, and according to this, dimensional dispersion is enlarged, whereby it is difficult to actually achieve the axial balance of the vertical deflecting coils
13
.
Further, since the plurality of elastic wedges
20
are attached to the circumferential outer surface of the coil separator
11
by applying adhesive, attachment position varies relying upon a worker, by which attachment position dispersion is enlarged, whereby it is further difficult to stably achieve the axial balance of the vertical deflecting coils
13
.
In addition, because the plurality of elastic wedges
20
are used, the number of components and cost are increased, and because the number of work steps including adhesive applying step for attaching the plurality of elastic wedges
20
is increased, workability and productivity are deteriorated.
Moreover, while one end and the other end of the horizontal deflecting coil
12
must be connected to the printed circuit board when it is disposed on the circumferential inner surface of the coil separator
11
, because pick-off positions are close to each other, one end a
Darby & Darby
Donovan Lincoln
Nguyen Tuyen T.
Samsung Electro-Mechanics Co., LTD
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