Method of manufacturing a shadow mask, shadow mask manufactured according to such a method, and colour display tube comprising such a shadow mask.

摘要

A shadow mask sheet manufactured from an iron-nickel alloy is drape-drawn by means of a drawing process to form a shadow mask 15. Prior to the actual drawing process theshadow mask sheet is subjected to an annealing treatment. After the drawing process the shadow mask is successively subjected to a complementary annealing treatment in a non-oxidizing gas atmosphere at a temperature between 700°C and 1200°C to improve the magnetic screening properties of the shadow mask 15, and to an annealing treatment in an oxidizing gas atmosphere. After oxidation the shadow mask 15 is connected on a supporting frame 17 which may be subjected to anannealing treatment in a non-oxidizing gas atmosphere and then to an oxidizing annealing treatment.