| 摘要 |
PURPOSE:To inhibit the deformation of a shadow mask by making it by the use of a complex plate which is prepared by superimposing upon each other a thin plate having a low Young's modulus and a low thermal expansion coefficient and a thin plate having a high Young's modulus and a high thermal expansion coefficient. CONSTITUTION:First, a complex plate is formed by superimposing upon each other a thin plate (A) made of an Invar alloy composed of 25-50% Ni, Fe and unavoidable impurities and a thin plate (B) with a Young's modulus of at least 20,000kg/mm<2> made of a mile steel composed of at most 0.1% C, at most 0.5% Mn, at most 0.5% Si and Fe. Next, the thermal expansion coefficient and the Young's modulus of the complex plate are adjusted to at most 8.0X10<-6>/ deg.C and at least 15,000kg/mm<2> respectively, thereby making a shadow mask for a color cathode-ray tube. This shadow mask favorably has both a low thermal expansion coefficient and high physical strength which are opposite properties. Therefore, it is possible to effectually prevent any color nonuniformity of images.
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