| 摘要 |
PURPOSE: A shadow mask is provided to have a strength enhanced relative to an impact, such as vibration and fall, so that the quality of a color cathode-ray tube can be kept constantly. CONSTITUTION: The shadow mask is made by arranging through holes(2a), comprising rear-side holes(4a), respectively, on the electron-beam incoming side, and front-side holes(3a), respectively, on the electron-beam outgoing side, and used to form beam spots of a prescribed shape on an irradiated surface. The through hole(2a) has ridgeline parts(8) formed where tapered surfaces(10) of the hole(4a) intersect tapered surfaces(6) of the hole(3a). The dimension of the taper, expressed by a half value of the difference between the hole width(S) at ends(7) of the hole(3a) and the hole width(Q) at the ridgeline parts(8), is caused to be 30% to 40% of the plate thickness of the shadow mask. The ridgeline parts are each formed so as to have a cross-section height(k) of 35 μm or less from end parts(9) of the hole(4a).
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