Electric lamp or space discharge component or device manufacturi – Process – With assembly or disassembly
Reexamination Certificate
1998-09-28
2001-09-04
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
With assembly or disassembly
Reexamination Certificate
active
06283814
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a flat cathode ray tube (CRT) and a method of manufacturing the flat CRT and, more particularly, to a flat CRT manufacturing method capable of forming a phosphor screen in a simplified manner while eliminating waste of the screen formation materials and mounting a tensioned mask within the CRT without a separate fixing device.
BACKGROUND OF THE INVENTION
Generally, CRTs are designed to reproduce the original picture image on a screen through receiving the picture image signals and exciting phosphors coated on the screen with electron beams in accordance with the signals. The CRT usually includes a panel having an inner phosphor screen, a funnel sealed to the rear of the panel with a neck for accommodating an electron gun therein, and a color selecting shadow mask placed directly behind the phosphor screen of the panel.
The panel is usually formed with a curved shape. However, this panel shape causes distortion of the picture image reproduced on the periphery of the screen, reflects light, and limits the viewing angle. Thus, a flat CRT having a flat panel screen has been intensively investigated. In the flat CRT, the shadow mask is also formed with a flat shape and a tensioned mask is mainly employed for that purpose.
Internal stress in the tensioned mask due to tensile force in all directions compensates for thermal expansion of the mask due to collision of the electrons to thereby prevent a doming phenomenon.
However, since there are strong tensile forces in the tensioned mask, a mask frame for supporting the tensioned mask should be rigid enough to prevent it from being deformed. For this purpose, the mask frame is usually very large and heavy.
With such a mask frame, it is not easy for the mask assembly to be attached to or detached from the panel for the light-exposing purpose during the phosphor screen formation process. For this reason, a master mask should be additionally employed only for the light-exposing step. However, in such a case, it is difficult to align the phosphor pixel pattern formed by the master mask with the beam-guide hole pattern of the CRT mask.
Korean patent application No. 97-21629 filed May 29, 1997 by the present Inventor discloses a three-piece flat CRT with a mid glass interposed between the panel and the funnel. For the phosphor screen forming purpose, a slurry coating method is employed. The tensioned mask is fixed to the mid glass by using a metal fixture. This structure enables the mask assembly to be easily attached to or detached from the panel during the phosphor screen formation process. In addition, a frit or bead glass may be used to fix the tensioned mask to the mid glass.
However, for the tensioned mask fixing purpose, the metal fixture or the frit glass may be surplus or its use may involve loose-fitting between the tensioned mask and the mid glass. Furthermore, the slurry coating method employed for the phosphor screen forming purpose involves waste of the screen formation materials and complicated processing steps.
SUMMARY OF THE INVENTION
It is an object of an embodiment of the present invention to provide a flat CRT and a method of manufacturing the flat CRT capable of forming a phosphor screen in a simplified manner while eliminating waste of phosphor materials and mounting a tensioned mask within the CRT without a separate fixing device.
In order to achieve this and other objects, an embodiment of the present invention provides a flat CRT including a front panel having an inner phosphor screen with a plurality of phosphor pixels and an inner edge side, a solid glass frame having a front side and a rear side, and a tensioned mask having a plurality of beam-guide holes corresponding to the phosphor pixels on the phosphor screen and an edge portion. The front panel is formed with a substantially flat shape. The front side of the solid glass frame is sealed to the edge side of the front panel. The edge portion of the tensioned mask is immersed in the solid glass frame. A funnel mounting a deflection yoke therearound and having a neck mounting an electron gun therewithin is sealed to the rear side of the glass frame.
The flat CRT manufacturing method includes the steps of printing a phosphor screen on an interior surface of a front panel with a printer, fixing a tensioned mask having a plurality of beam-guide holes to a glass frame, sealing the glass frame to the front panel, and sealing a funnel to the glass frame.
REFERENCES:
patent: 4593225 (1986-06-01), Dietch et al.
patent: 4925421 (1990-05-01), Van Den Broek
patent: 4964828 (1990-10-01), Patt et al.
patent: 5343803 (1994-09-01), Duchek et al.
Christie Parker & Hale LLP
Hopper Todd Reed
Patel Nimeshkumar D.
Samsung Display Devices Co., Ltd
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