Electric lamp and discharge devices – Cathode ray tube – Shadow mask – support or shield
Reexamination Certificate
1998-12-11
2001-05-01
Day, Michael H. (Department: 2879)
Electric lamp and discharge devices
Cathode ray tube
Shadow mask, support or shield
C313S407000, C313S408000
Reexamination Certificate
active
06225734
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cathode-ray tube having a flat face, and more particularly, to a cathode-ray tube in which the installation structure of a tension mask is improved.
2. Description of the Related Art
In a color cathode-ray tube, electron beams emitted from electron guns pass through electron beam passing holes of a shadow mask which has a color separation function and land on a phosphorescent film, and thereby excite a phosphorescent material to form images.
The screen surface of a conventional color cathode-ray tube is designed to have a predetermined curvature considering trajectories of electron beams emitted from the electron guns and deflected by a deflection yoke, and also the shadow mask is designed to have a curvature corresponding to the curvature of the screen surface. During the operation of the color cathode-ray tube having the structure as above, the shadow mask is heated by the electron beams, i.e., thermal electrons emitted from the electron guns and experiences a doming effect in which the shadow mask domes toward the screen. The doming effect causes the electron beams to land not exactly on the phosphorescent screen. In addition, since the screen surface of a conventional color cathode-ray tube has the predetermined curvature, there are problems in which the angle of view is narrow and images are distorted at the edge portions of the screen surface.
A cathode-ray tube having a flat screen surface is developed in order to solve the above problems, and comprises a flat panel provided with a phosphorescent film and a mask fixed to the panel in a state applied with a predetermined tension.
FIG. 1
shows a support system for a tension mask of a cathode-ray tube having a flat face, and the support system is disclosed in U.S. Pat. No. 4,900,977. As shown in
FIG. 1
, a support frame
12
is fitted to a panel
11
provided with a sealing portion
11
a along the peripheral part of the panel
11
, and a tension mask
13
is fixed to the upper edge of the support frame
12
.
In the above structure, the stepped sealing portion
11
a
must be provided along the peripheral part of the panel
11
in order to fix the tension mask
13
to the panel
11
. Further, distance deviation between the tension mask
13
and the phosphorescent film formed on the inner surface of the panel
11
may be serious depending on the fixation state of the support frame
12
to the panel
11
.
SUMMARY OF THE INVENTION
To solve the above problems, it is an objective of the present invention to provide a cathode-ray tube having a flat face in which the distance between a tension mask and a panel can be uniformly maintained.
Accordingly, to achieve the above objective, there is provided a cathode-ray tube having a flat face including a panel having a flat screen surface and provided with a support portion at the inner surfaces of a skirt portion at the periphery thereof, a frame supported by the support portion of the panel, a flat tension mask fixed to the frame in a tensioned state, and a funnel joined to the panel for end thereof to support the frame.
According to another embodiment of the present invention, there is provided a cathode-ray tube having a flat face including a panel having a flat screen surface and provided with a skirt portion at the periphery thereof, a frame joined to the skirt portion to contact the inner surfaces thereof, a flat tension mask fixed to the frame in a tensioned state, a gap maintaining member interposed between the frame and the screen surface of the panel, and a funnel joined to the panel for end thereof to support the frame.
According to still another embodiment of the present invention, there is provided a cathode-ray tube having a flat face including a panel having a flat screen surface and provided with a skirt portion at the periphery thereof, a frame having a predetermined thickness and installed to contact the periphery of the screen surface of the panel, a flat tension mask fixed to the frame in a tensioned state and maintaining a predetermined gap with respect to the screen surface of the panel, and a funnel joined to the panel for end thereof to support the frame.
According to still another embodiment of the present invention, there is provided a cathode-ray tube having a flat face including a panel having a flat screen surface and provided with a skirt portion at the periphery thereof, a frame joined to the skirt portion to contact the inner surfaces thereof, a flat tension mask fixed to the frame in a tensioned state, a supporting device installed at the skirt portion for supporting the frame, and a funnel joined to the panel for end thereof to support the frame.
REFERENCES:
patent: 4739215 (1988-04-01), Adamski et al.
patent: 5532545 (1996-07-01), Okamoto et al.
patent: 5952774 (1999-09-01), Diven et al.
Day Michael H.
Lowe Hauptman & Gilman & Berner LLP
Samsung Display Devices Co. Ltd.
Williams Joseph
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