| 摘要 |
PROBLEM TO BE SOLVED: To stably stretch and mount a masking plate on a frame by welding the masking plate with a number of apertures arranged in a rectangular area encircled by two long sides and two short sides while stretching it at a tension different from that in the long-side direction. SOLUTION: A pair of crips 16, 17 to hold the outsides 6c, 6d of two short sides in a holed rectangular area 13 on a masking plate 6 are used to stretch the masking plate 6 at a tension of 19.9kg/mm<2> , somewhat smaller than yielding point stress in the long-side direction. The masking plate 6 is welded to four sides 9-12 of a frame 7, either at a proper value smaller than the strength in the long-side direction of the masking plate 6 or at a proper value not higher than the strength in the short-side of an aperture 8 in the masking plate 6. To surely prevent the breakage of the masking plate and always apply correct tension to the masking plate when used as a color selecting electrode for a color picture tube, respective tensions in the long- and short-side directions can be set within±20% of respective yielding point stresses.
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