PRODUCTION OF MASTER PLATE FOR SHADOW MASK

摘要

PURPOSE:To obtain a master plate for a shadow mask which permits formation of fine holes for passage of an electron beam with high accuracy by subjecting a material which consists of specific lattice structure and is cold rolled at a high draft to a heat treatment at the recrystallization temp. or above so as to aggregate the specific crystal faces to the rolled plane. CONSTITUTION:The shadow mask material consisting of an ''Invar(R)'' alloy or the like having face-centered cubic lattice structure or body-centered cubic lattice structure is strongly rolled cold at about >=80% draft. Such material is heat-treated at the recrystallization temp. of said alloy or above to aggregate the (100) crystal faces to the rolled plane. The rolled material is further cold rolled at >=25% draft is necessary. The master plate for the shadow mask obtd. by the above-mentioned method permits formation of the holes for passage of the electron beam with high accuracy and high density. The doming occurring in the thermal expansion of the shadow mask is prevented by selecting the material, by which the original plate is made to meet the purpose of a high-grade television.