The design of flat shadow mask for improvement definition CPT

The design method of flat shadow mask for CPT (Color Picture Tube) used for MMTV (Multimedia TV) is presented. At the same time, the curved surface shape of stamping mould keeps unchanged, therefore the expense is saved and design and manufacturing period is shortened. The 25 inch CPT's flat shadow mask is computed and manufactured. New CPT is assembled and tested, its horizontal resolution up to 700 lines from original about 500 lines. Moire effect could not be viewed. The picture quality is good.