Electric lamp and discharge devices – Cathode ray tube – Beam deflecting means
Reexamination Certificate
2002-03-28
2004-09-14
Patel, Ashok (Department: 2879)
Electric lamp and discharge devices
Cathode ray tube
Beam deflecting means
C313S47700R, C335S209000, C335S296000, C252S06251C
Reexamination Certificate
active
06791252
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates to a deflection yoke, in particular, which can reduce power consumption while elevating deflection sensitivity.
2. Description of the Prior Art
In general, a Cathode Ray Tube (CRT) in a television or a monitor has a deflection yoke for correctly deflecting RGB beams scanned from an electron gun to a fluorescent screen applied on a screen of the CRT. Such a deflection yoke functioning as one of the most important magnetic components in the CRT serves to deflect the electron beams from the electron gun so that electric signals transmitted in time sequence can be reproduced as images on the screen of the CRT.
In other words, since the electron beams project ed from the electron gun directly move onto the screen with a high voltage to light only central phosphors in the screen, the deflection yoke externally deflects the electron beams in the order of scanning. Here, the deflection yoke forms a magnetic field to deflect the electron beams correctly to the fluorescent screen applied on the screen of the CRT based upon the fact that the electrons are forced to change the course thereof while passing through the magnetic field.
FIG. 1
is a side elevation view for showing a general CRT. As shown in
FIG. 1
, a deflection yoke
4
is placed in an RGB electron gun section
3
of the CRT
1
to deflect electron beams scanned from an electron gun
3
a
toward a fluorescent screen applied on a screen surface
2
.
Such a deflection yoke
4
comprises a coil separator
10
constituted of a pair of symmetric upper and lower parts which are coupled into one unit.
The coil separator
10
is provided to mutually insulate horizontal deflection coils
15
and vertical deflection coils
16
while assembling the same at suitable positions, and comprised of a screen portion
11
a
for being coupled to one side of a screen surface of the CRT
1
, a rear cover
11
b
and a neck portion
12
integrally extended from a central surface of the rear cover
11
b
for being coupled to the electron gun section
3
of the CRT
1
.
The coil separator
10
is respectively provided in the inner and outer peripheries with the horizontal deflection coils
15
and the vertical deflection coils
16
for forming horizontal magnetic deflection and vertical magnetic deflection via externally applied power.
Further, a pair of ferrite cores
14
made of a magnetic substance are installed to wrap the vertical deflection coils
16
to strengthen the vertical magnetic deflection generated from the vertical deflection coils
16
.
The deflection yoke
4
configured like this is installed in the neck portion
12
of the CRT
1
. When the horizontal deflection coils
15
and the vertical deflection coils
16
are applied with a sawtooth wave pulse, the deflection yoke
4
generates the magnetic field based on the Fleming's left hand rule to deflect the RGB electron beams emitted from the electron gun
3
a
of the CRT so as to determine scanning positions on the screen.
In the above deflection yoke
4
, the deflection coils and ferrite cores
14
as well as the coil separator
10
are designed according to the tube shape of the CRT
1
.
As shown in
FIG. 2
, in other words, the conventional deflection yoke
100
is configured to have horizontal deflection coils
120
for forming a horizontal magnetic deflection and vertical deflection coils
130
for forming a vertical magnetic deflection, in which the horizontal deflection coils
120
are provided in the inner periphery and the vertical deflection coils
130
are provided in the outer periphery about the coil separator
110
so that the coils
120
and
130
form concentric circles.
The vertical deflection coils
130
are provided in the outer periphery with a ferrite core
140
for strengthening the vertical magnetic deflection from the vertical deflection coils
130
as above. The ferrite core
140
also has a circular sectional shape.
As shown in
FIG. 3
, the coil separator
110
is formed into the shape of a funnel in general, and comprised of a screen portion
111
having a large diameter, a neck portion
114
having a small diameter, a body
112
connecting between the screen portion
111
and the neck portion
114
and a rear cover
113
having the shape of boards at a position adjacent to the neck portion
114
. The coil separator
110
mutually insulates the horizontal deflection coils
120
and the vertical deflection coils
130
, as shown in
FIG. 2
, while maintains the same in suitable positions.
In the conventional deflection yoke
100
, however, the CRT section to which the deflection yoke
100
is attached is manufactured into a circular shape due to difficulty in manufacture even though the screen surface of the CRT has a rectangular shape with an aspect ratio of 4:3 or 16:9 thereby resulting in problems that enhancement of deflection sensitivity is restricted and power consumption increases as well.
As CRTs of TVs or monitors are flattened or large sized recently, the CRTs require those deflection yokes which can guarantee high deflection sensitivity. However, since the deflection yokes have circular cross sections, there are limitations in increasing deflection efficiencies according to traces of the electron beams.
In order to solve the above problems, a ferrite core having a quadrangular cross section was proposed in the prior art. However, the following problems are incurred in forming the ferrite core into the quadrangular shape.
In general, since the ferrite core is formed through compression molding, it has a very poor workability. Also, the ferrite core requires a precise working process thereby lowering the productivity and increasing the manufacturing cost by a large margin.
In other words, the ferrite core having the cross section manufactured into the angled shape has an ununiform contraction dispersion which is generated by a large amount in a plastic deformation process over the ferrite core having the circular cross section. This accompanies a working process for improving the dispersion, thereby increasing the number of process steps and lowering the yield.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made to solve the above problems and it is an object of the present invention to provide a deflection yoke which comprises a coil separator and horizontal deflection coils having angular cross sectional shapes and a ferrite core and vertical deflection coils having circular cross sectional shapes to improve deflection sensitivity thereby reducing power consumption.
It is another object of the invention to provide a deflection yoke which comprises support structures in an outer periphery of a coil separator at the same interval for supporting horizontal deflection coils with an angular cross section, vertical deflection coils with a circular cross section and a ferrite core so as to improve deflection sensitivity as well as enhance mass productivity.
According to an aspect of the invention, it is provided a deflection yoke comprising: a coil separator formed into the shape of a quadrangular pyramid with a quadrangular cross section, and comprising a screen portion coupled to a screen of a CRT and a neck portion integrally extended from said screen portion and coupled to an electron gun section of the CRT; horizontal and vertical deflection coils provided in inner and outer peripheries of said coil separator for forming magnetic deflections to deflect electron beams in horizontal and vertical directions; and a ferrite core provided in the outside of said coil separator and having a substantially conical shape for strengthening the magnetic deflections.
The deflection yoke is further characterized in that said vertical deflection coils closely contact to an outer surface of said coil separator.
The deflection yoke is characterized in that said vertical deflection coils closely contact to an inner surface of said ferrite core.
The deflection yoke is further characterized in that said horizontal deflection coils are angularly wound to close
Choi Hwan Seok
Kim Jung Sub
Kim Seoung Chun
Lee Cheong Moon
Darby & Darby
Harper Holly
Patel Ashok
Samsung Electric-Mechanics Co. Ltd.
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