Electric lamp and discharge devices – Cathode ray tube – Beam deflecting means
Reexamination Certificate
2000-12-07
2003-02-18
Kim, Robert H. (Department: 2882)
Electric lamp and discharge devices
Cathode ray tube
Beam deflecting means
C335S210000, C335S213000
Reexamination Certificate
active
06522060
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a deflection yoke for Braun tube, and more particularly, to a deflection yoke for Braun tube having a pair of horizontal deflection coil and a vertical deflection coil formed in a half-muscle type in which the height of a first neck flange coil of the horizontal deflection coil and the length of a main deflection part coil are in a predetermined ratio for the length of a second neck flange coil, to thereby optimize a neck shadow and improve a deflection sensitivity and a screen adjustment characteristic (Integrated Tube Component).
2. Description of the Background Art
FIG. 1
is a schematic sectional view showing internal structure of a general Braun tube in accordance with a conventional art.
As shown in the drawing, a general Braun tube includes an electron gun
4
for discharging three electron beams
7
, a screen
1
on which the electron beams
7
hit to produce an image, a shadow mask
2
for discriminating the three electron beams
7
, a deflection yoke
3
for deflecting the electron beams onto a predetermined fluorescent face of the screen
1
.
Reference numeral
5
denotes a panel,
6
a
denotes a screen unit of a funnel, and
6
b
denotes a neck part of the funnel.
Thusly constructed Braun tube performs a function to receive an electric signal for a picture from an external source and change it to a light signal so as to be displayed as a picture having functions of a position and a content (color) on the fluorescent face of the screen.
Accordingly, the content signal having information on the color of the picture displayed on the screen is applied to the electron gun
4
, and a color combination of a red (R) electron beam, a green (G) electron beam and a blue (B) electron beam is appropriately made to display a desired color on the screen.
The content signal of the picture is applied to the deflection yoke
3
, so that the position point of the screen which the R, G and B electron beams radiated from the electron gun
4
reach is adjusted to display a desired picture.
FIG. 2
shows a detailed view of the deflection yoke. As shown in the drawing, the deflection yoke
3
includes a horizontal deflection coil
31
for horizontally deflecting the electron beam radiated from the electron gun
4
installed in Braun tube, a vertical deflection coil
33
for vertically deflecting the electron beam the electron beam, a conical ferrite core
34
for reducing the loss of a magnetic force generated from the horizontal deflection coil
31
and the vertical deflection coil
33
, to heighten magnetization efficiency, and a holder
32
for fixing the horizontal and vertical deflection coils
31
and
33
and the ferrite core
34
at a determined position and for insulating the horizontal deflection coil
31
and the vertical deflection coil
33
.
After the thusly constructed deflection yoke
3
is mounted at the neck part, when current is applied to the horizontal deflection coil and the vertical deflection coil, a desired picture is displayed on the screen.
The operation of the general deflection yoke
3
constructed as described above will now be explained.
Generally, current having a frequency of 15.75 KHz or more flows to the horizontal deflection coil
31
of the deflection yoke, to generate a magnetic field. By using the magnetic field, the electron beams inside Braun tube are deflected in the horizontal direction.
Likewise, current which usually has a frequency of 50 Hz flows to the vertical deflection coil
33
, to generate a magnetic field. By using the magnetic field, the electron beams are deflected in a vertical direction.
Recently, a self-convergence type deflection yoke has been developed in which, by virtue of a nonuniform magnetic field according to the horizontal deflection coil
31
and the vertical deflection coil
33
, the three electron beams can make a convergence on the screen even without any supplementary circuit or any supplementary unit.
That is, the winding distributions of the horizontal deflection coil
31
and of the vertical deflection coil
33
are adjusted to generate a barrel type magnetic field or a pin-cushion type magnetic field by regions (i.e., an opening part (a screen flange unit), a middle part or a neck part, etc). Thus, the three electron beams have different deflection forces each other, so that the electron beams can be converged into the same point in different distances from the starting positions of the electron beams to the screen
1
, the reaching position.
In the case that current flows to the horizontal and vertical deflection coils
31
and
33
to generate a magnetic field, since it is difficult to deflect the electron beams onto the entire surface of the screen only with the magnetic field according to the horizontal and vertical deflection coils
31
and
33
, the ferrite core
34
of high permeability is used to minimize the loss on the return path of the magnetic field, thereby heightening the efficiency of the magnetic field and thus increasing the magnetic force.
Also, in order to heighten the deflection sensitivity, generally, the deflection coil is moved toward the electron gun. In this case, however, a problem arises that the neck shadow (a region formed in order for the deflected electron beam to hit the funnel portion to thereby prevent the electron beam from reaching the screen) is shortened.
Reversely, in case that the deflection coil is moved toward the screen to obtain a sufficient space for the neck shadow, since the deflection sensitivity representing a capability in deflecting the entire screen is deteriorated due to a constant amount of current applied from an external source. Thus, in this case, more current needs to flow thereto.
Accordingly, the deflection sensitivity and the neck shadow are hardly compatible. In an effort to solve the problem, there has been proposed a coil winding type of a half muscle type coil, that is, a medium type between the flange type coil and the muscle type coil.
FIGS. 3A and 3B
are perspective view showing a flange type coil and a muscle type coil in accordance with the conventional art.
As shown in
FIG. 3A
, in case of the flange type coil, once the length and a position are determined in a simulation, a complementing coverage to complement it during designing is very limited.
For example, a method for complementing the deflection sensitivity during designing exists merely to make an electrically connected state. Actually, in order to complement the deflection sensitivity, the flanges
31
a
and
31
b
, portions where a magnetic field for making deflection is not almost generated, and especially, the flange
31
a
of the opening, are to be minimized and the position of a main deflection portion coil
31
d
, that is, the portion which generates a main deflection magnetic field is to be complemented.
However, in this case, since the form of a frame mechanically configuring the flange type coil should be changed, it is very difficult to complement it during designing.
Meanwhile, in case of the muscle type coil, as shown in
FIG. 3B
, unlike the flange type coil, it doesn't have a flange at the neck portion, so that the position of a window can be adjusted to control the sensitivity to a level and adjust the neck shadow. However, it is disadvantageous in that the overall length of the deflection yoke coil is changed due to the basic form size and position, limiting its designing operation for an optimum setting.
FIG. 4
is a perspective view of a general half-muscle type deflection coil in accordance with the conventional art,
FIGS. 5A
though
5
C are respectively a front view, a side view and a plan view of the general half-muscle type deflection coil in accordance with the conventional art, and
FIG. 6
is a view showing a pattern of a misconvergence of a screen according to a deflection coil in accordance with the conventional art.
As shown in the drawings, the half-muscle type horizontal deflection coil
31
or the half-muscle type vertical deflection coil
33
have a form that
Fleshner & Kim LLP
Gemmell Elizabeth
Kim Robert H.
LG Electronics Inc.
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