| 摘要 |
PURPOSE:To prevent the deterioration of the color purity due to the thermal expansion of a shadow mask by constructing the shadow mask with a material composed mainly of Fe-Ni alloy and plating a Ni-P family alloy on the surface after annealing at a high temperature and press forming. CONSTITUTION:A color picture tube is constructed by providing the fluorescent screen 14, the electron gun 16, the shadow mask 15 and so on in an envelope consisting of the panel 11, the funnel 12 and the neck 13. The shadow mask 15 is made of a material composed mainly of Fe-Ni family alloy such as invar or the like, and it is formed to a specified curved surface by press forming after annealing in vacuum at a high temperature. Then the surface is plated with a Ni-P family alloy by electroless plating and so on, and the blackening process is applied to the surface to construct the shadow mask. Thus the mechanical strength of the shadow mask 15 is improved while keeping the low thermal expansion characteristics. thereby the deterioration of the color purity due to the heating and the vibration can be prevented effectively.
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