Shadow mask assembly with three therman expansion coefficients

Abstract

A shadow mask assembly is provided, which reduces the necessary tensile force to be applied to the shadow mask and the weight and fabrication cost of the assembly itself. This assembly is comprised of (a) a pair of bars arranged in substantially parallel at a specific distance; the pair of bars being made of metal having a first thermal expansion coefficient; (b) a pair of arms fixed to the pair of bars in such a way that each of the pair of arms links the pair of arms together; the pair of arms applying a force that moves the pair of bars away from each other; the pair of arms being made of metal having a second thermal expansion coefficient; the pair of arms constituting a frame having an approximately rectangular opening along with the pair of bars; and (c) a shadow mask fixed to the pair of the bars so as to cover the opening of the frame; the shadow mask being applied with a tensile force in a direction approximately perpendicular to the pair of bars due to the force of the pair of arms that moves the pair of bars away from each other, thereby keeping the mask in its specific shape; the shadow mask being made of metal having a third thermal expansion coefficient that is low enough for suppressing the doming phenomenon; the third thermal expansion coefficient of the mask being less than the second thermal expansion coefficient of the pair of arms.