BLACKENED FILM FORMING METHOD FOR SHADOW MASK

摘要

PURPOSE:To form a blackened film on the surface of a shadow mask material without generation its deformation by arranging shadow mask with its protrud ing surface of spherical part faced downward, supporting the non-opened part from below, and by heating it. CONSTITUTION:A number of openings are bored in a sheet consisting of amber whose main component is Fe and Ni, and a shadow mask material 14 thus obtained and further provided with a spherical part and a skirt part is accommo dated in a blackening cage 11. This shadow mask material 14 is supported at its peripheral non-bored part by a retainer 13 from below and fixed, with the spherical part facing up and skirt part down. They are carried into a blackening furnace cage 11 by cage and heated in the atmosphere of a mixture gas of CO2 and CO. Thus a blackened film is accomplished.