Shadow mask in color cathode ray tube

Details Shadow mask in color cathode ray tube Shadow mask in color cathode ray tube

2001-04-23

2004-02-10

Patel, Ashok (Department: 2879)

Electric lamp and discharge devices

Cathode ray tube

Shadow mask, support or shield

C313S403000

Reexamination Certificate

active

06690104

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cathode ray tube, and more particularly, to a shadow mask in a color cathode ray tube.
2. Background of the Related Art
Referring to
FIG. 1
, in general, the color cathode ray tube is provided with a panel
1
having R, G, B fluorescent films coated on an inside surface, a funnel
1
fusion welded to a rear end of the panel
1
for keeping inside of the color cathode ray tube in vacuum, an electron gun
5
sealed in a neck portion
3
of the funnel for emitting electron beams
4
, a deflection yoke
6
for deflecting the electron beams emitted from the electron gun, and a shadow mask
7
for selecting a color of the electron beams deflected by the deflection yoke. Together with these, there are a frame assembly
8
for supporting the shadow mask
7
, and springs
9
for fastening the frame assembly
8
to the panel
1
in the color cathode ray tube.
A picture reproducing process of the color cathode ray tube will be explained.
Upon reception of a video signal at the electron gun
5
sealed in the neck portion
3
of the funnel
2
, electron beams
4
are emitted from cathodes (not shown) in the electron gun, controlled, accelerated, and converged, and modified of their paths in vertical and horizontal directions by a magnetic field of the deflection yoke
6
, pass through the shadow mask
7
, hit the fluorescent film
10
on the inside surface of the panel
1
, to emit light and reproduce a picture.
Referring to
FIG. 2
, a related art shadow mask
7
will be explained in detail.
The shadow mask
7
is fitted to the panel
1
with a gap from the fluorescent film (see reference numeral
10
in FIG.
1
). The color shadow mask
7
of a thin steel shielding plate has a plurality of slots
7
a
formed in the surface, each with a very small size to an extent almost invisible, which indicates that an amount of the electron beams passed through the slot
7
a
is very little, resulting in an amount of the electron beams that make the fluorescent film luminant is very little, to make a luminance, that gives a great influence to a quality of the color cathode ray tube, poor. Especially, an importance of the luminance becomes the greater day by day such that U.S. Pat. No. 4,926,089, and USP 4,942,332 are filed, according to which necessity for improving the luminance is kept increasing.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a shadow mask in a color cathode ray tube that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a shadow mask in a color cathode ray tube, which can improve a luminance, prevent moiré and doming in advance, and improve an effect of shadow elimination caused by an opened bridge.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the shadow mask in a color cathode ray tube includes a plurality of slots for passing electron beams therethrough, and a bridge between adjacent slots in a height direction, wherein a portion of the bridge is removed to combine a number of the slots, such that a removal area of the bridge is 1~30% of an area of the bridge.
In another aspect of the present invention, there is provided a shadow mask in a color cathode ray tube including a plurality of slots for passing electron beams therethrough, and a bridge between adjacent slots in a height direction, wherein a portion of the bridge is removed to combine a number of the slots, such that an open width of the bridge is 1~40% of a slot width.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.


REFERENCES:
patent: 4926089 (1990-05-01), Moore
patent: 4942332 (1990-07-01), Adler et al.
patent: 5055736 (1991-10-01), Yun et al.
patent: 6437496 (2002-08-01), Kim et al.
patent: 6472806 (2002-10-01), Kim et al.

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