Electric lamp and discharge devices – Cathode ray tube – Beam deflecting means
Reexamination Certificate
1998-11-13
2001-08-28
Day, Michael H. (Department: 2877)
Electric lamp and discharge devices
Cathode ray tube
Beam deflecting means
C313S442000, C335S210000
Reexamination Certificate
active
06281623
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a core for a deflecting yoke (deflection yoke) and to a deflecting yoke (deflection yoke), which are used for a CRT (Cathode Ray Tube) and capable of enhancing a deflection sensitivity and reducing electric power consumed.
2. Description of the Prior Art
A conventional CRT is constructed of a display panel, a funnel and a neck. A core for a deflection yoke is provided covering some portions of the funnel and the neck. The deflection yoke using such a deflection yoke core deflects an electron beam emitted from an electron gun provided at the neck. In the typical deflection yoke core, configurations of neck-and funnel-side aperture edge surfaces are circular, and the deflection yoke is constructed in such a way that horizontal and vertical windings called a saddle type coil are provided on the side of an inner surface of the core.
According to, e.g., Japanese Patent Publication No.8-28194, as shown in
FIGS. 1 through 3
, a deflection yoke core (a round uniform slot type core)
1
of which a sectional configuration is circular includes a plurality of protruded portions
1
a
provided consecutively from a side (a neck side) with an inner surface having a small diameter toward a side (a funnel side) having a large diameter, and grooved portions
1
b
are formed between the protruded portions
1
a
. Windings (vertical and horizontal windings)
4
are, as shown in
FIG. 4
, disposed in the grooved portions
1
b
, thus constructing a winding structure known as a slot system.
FIG. 1
is a diagram of the deflection yoke core
1
as viewed from the funnel side,
FIG. 2
is a diagram of the deflection yoke core
1
as viewed from the neck side, and
FIG. 3
is a diagram showing an external portion
5
a
and a sectional portion
5
b
of the deflection yoke core
1
.
In the deflection yoke core disclosed in Japanese Patent Publication No.8-28194, however, a sectional configuration of the CRT on the funnel side is circular, and, in the case of using this core, a geometrical distortion property and a mis-convergence property of the deflection yoke are substantially equal to the properties in the case of a typical deflection yoke core. Therefore, despite such a main trend that a sectional configuration of the display panel of the CRT is a rectangle exhibiting an aspect ratio of 4:3 or 16:9, a configuration of a portion, fitted with the deflection yoke, of the CRT is circular in terms of a manufacturing problem, with the result that there might be a limit in terms of enhancing the deflection sensitivity of the electron beam.
Further, Japanese Patent Application Laid-Open Publication Nos.8-7781 and 8-7792 each disclose a deflection yoke core, wherein the sectional configuration is, as shown in
FIG. 5
, an ellipse other than the circle. Referring again to
FIG. 5
, an outer surface configuration of a funnel-side section is an ellipse as indicated by four circular segments ab, bc, cd, da. In particular, the circular segments ab, cd have radii R
1
having the same length, of which the center is an origin O of the X- and Y-axis coordinates. The circular segments bc, da have radii R
2
having the same length, of which centers are symmetrical points S. S′ on the Y-axis. Herein, let P, Q be nodal points between the circular segments bc, da and the Y-axis, and there is established a relationship such as OP (OQ)<R
1
. A capacity of the cone portion is thereby made smaller than that of the circular core, thus reducing deflection power. Further, the outer surface configuration of the core
2
is, as shown in
FIG. 5
, so formed as to contain the circular segment having the maximum radius R
1
of which the center is the origin O of the X- and Y-axis coordinates. With this contrivance, a conventional sintering frame
3
for the circular core, which is formed with an aperture
3
a
having the radius R
1
as indicated by the broken line in
FIG. 5
, can be used when manufacturing the core assuming the elliptical configuration of the outer surface by sintering.
In the deflection yoke core disclosed in Japanese Patent Application Laid-Open Publication No.8-7781, however, in order to make usable the conventional sintering frame formed with the round aperture when in the sintering process, the funnel-side outer surface configuration is elliptical, and there is neither disclosed anything about an inner surface configuration thereof nor mentioned specifically an improvement of a deflection sensitivity.
SUMMARY OF THE INVENTION
It is an object of the present invention, which has been made under such circumstances, to provide a core for a deflection yoke and a deflection yoke using the deflection yoke core for attaining an enhancement of the deflection sensitivity by taking an angular structure in which a sectional configuration of the deflection yoke core is analogous to a shape of a display panel of a cathode ray tube, especially an inner periphery of a funnel-side aperture edge surface is approximately rectangular.
According to the present invention, in a core for a deflection yoke for a cathode ray tube including a rectangular display panel, an aperture edge surface on the side of the neck portion takes a circular configuration, an inner periphery of an aperture edge surface on the side of the funnel portion takes a configuration of an approximate rectangle corresponding to a configuration of the display panel, and each of sides of the approximate rectangle contains an approximately rectilinear portion. The present invention is applied particularly to the cathode ray tube having the rectangular display panel, and it is feasible to extremely effectively enhance a deflection sensitivity and reduce the electric power consumed. In this case, the inner periphery of the sectional configuration of the funnel portion in the direction substantially perpendicular to the direction from the neck portion toward the funnel portion, is also analogous to this approximate rectangle.
Further, in the deflection yoke core according to the present invention, a neck-side aperture edge surface takes a circular configuration. A plurality of protruded portions are radially provided along an inner surface, extending from the side of the neck portion to the side of the funnel portion, in which case an envelope configuration of bottom surfaces of a plurality of grooved portions formed between the plurality of protruded portions with respect to the aperture edge surface on the side of the funnel portion, is approximately rectangular corresponding to the configuration of the display panel. Each of sides of the approximate rectangle contains an approximately rectilinear portion. Even when the plurality of protruded portions are provided along the inner surface, the deflection sensitivity can be thereby effectively enhanced. The coil is disposed in the grooved portion between the protruded portions, thereby making it feasible to concentrate a magnetic flux at a high efficiency and to further enhance the deflection sensitivity.
With respect to the aperture edge surface configuration on the side of the neck portion, if the core does not include the protruded portions provided along the inner surface, and if the protruded portions do not extend to the aperture edge surface on the side of the neck portion, the inner peripheral configuration is circular. Further, if the protruded portions are formed extending to the aperture edge surface on the side of the neck portion, the envelope configuration of the bottom surfaces of the grooved portions between the protruded portions, is circular.
Moreover, the deflection yoke core may further comprise a plurality of separating protruded portions provided separately on the side of the neck portion and the side of the funnel portion. The number of the protruded portions provided on the side of the funnel portion maybe different from the number of the protruded portions provided on the side of the neck portion. Further, at least a part of the plurality of protruded portions may be non-radially provided. With these
Iimura Kazuyuki
Ito Shinitirou
Iwaya Hitoshi
Kashiwaba Nobuya
Kinoshita Yukiharu
Day Michael H.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
TDK Corporation
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