Shadow mask having a curved surface with compressed, strengthening dents

摘要

A shadow mask including a perforated portion that has a desired curved surface shape is obtained by pressing a flat mask having electron beam apertures. The press-molded perforated portion of the shadow mask is compressed in its thickness direction in a manner such that it is sandwiched between a first compression mold, having a convex surface that faces a concave surface of the perforated portion in which smaller holes of the electron beam apertures open and a plurality of projections on the convex surface, and a second compression mold, having a smooth concave surface that faces the convex surface of the perforated portion in which larger holes of the electron beam apertures open. In doing this, the perforated portion is locally compressed by means of the projections of the first compression mold, whereby a plurality of recesses are formed on the concave surface side of the perforated portion.