Electric lamp or space discharge component or device manufacturi – Process – With testing or adjusting
Patent
1996-05-07
1997-12-02
Bradley, P. Austin
Electric lamp or space discharge component or device manufacturi
Process
With testing or adjusting
445 30, 445 63, 445 68, H01J 918, H01J 942
Patent
active
056929412
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method of and an apparatus for welding a panel attachment spring to an aperture grill forming a color cathode-ray tube (hereinafter simply referred to as a CRT).
BACKGROUND ART
In a CRT employing an aperture grill as a color selection mechanism for use in a television receiver and a monitor television receiver of a computer, an aperture grill with a large number of slits formed therethrough is attached to an inside of a panel coated on its inner surface with fluorescent paints of three primary colors (R, G, B). Three primary color electron beams emitted from an electron gun pass through the slits of the aperture grill and are radiated on fluorescent paint portions of corresponding colors on the inner surface of the panel.
The above aperture grill includes a substantially rectangular frame formed of four members of upper, lower, left and right members, and a grill stretched between the upper and lower members. A large number of the above-mentioned slits are formed through the grill extended vertically at portions with intervals from its left and right.
The above panel includes a substantially rectangular panel portion coated on its inner surface with the above fluorescent paints and four skirt portions of upper, lower, left and right skirt portions, projectingly formed so as to be extended from four sides of the panel portion toward the inside of the tube. The panel portion is formed so as to have a little larger size as compared with the above grill.
The above aperture grill is attached to the panel by engaging pin apertures of panel attachment springs welded to the three or four members of the aperture grill with pins (so-called panel pins) fitted to inner surfaces of the three or four skirt portions of the panel.
If an interval between a grill surface and the inner surface of the panel portion is different from a design value in a state that the aperture grill is attached to the panel as described above, then the electron beams passed through the slits of the grill are not accurately radiated on the corresponding fluorescent paint portions of the panel portion, which leads to defects of an assembled CRT such as an erroneous landing of beams or the like.
Therefore, it is important to accurately set particularly the interval at any portion between the grill surface and the inner surface of the panel portion to the design value at any places in a CRT requiring high definition such as the monitor television receiver of the computer, a CRT having a large screen size and so on. For this end, it is necessary to accurately position the pin aperture of the spring relative to the grill.
In the prior art, there is increased an accuracy of a position where the springs are welded to the respective members of the above frame.
However, it is sometimes observed that the above frame is twisted by strains of its respective members or the like. In this case, the grill is twisted similarly to the frame. Accordingly, even if the accuracy of the spring welded positions relative to the respective members is increased, the positions of the pin apertures of the springs relative to the grill are displaced because of the twisted grill. This positional displacement prevents the interval between the grill surface and the inner surface of the pane portion in the state that the aperture grill is attached to the panel, from deviating from the design value at some places. Therefore, defects such as the erroneous landing of the beams or the like cannot be prevented surely.
Since the springs are welded to the respective members in consideration of only the positional accuracy of the spring relative to each of the members in the prior art, it is not known before the welding of the springs whether or not positions of the pins of the respective springs are set to positions where the interval (a so-called grill height GH) between the grill surface and the inner surface of the panel portion in the state that the aperture grill is attached to the panel is always set to the design value at a
REFERENCES:
patent: 4164060 (1979-08-01), Hartta
patent: 4356606 (1982-11-01), Dougherty et al.
patent: 4451243 (1984-05-01), D'Augustine et al.
Kojima Yoshirou
Kurihara Tomoyuki
Otsuka Kazuhiko
Takeda Masami
Bradley P. Austin
Knapp Jeffrey T.
Sony Corporation
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